JP5757466B2 - Filler material and overlay metal member using the same - Google Patents

Description

  The present invention relates to a filler material and a built-up metal member using the same, and in particular, a filler material made of martensitic stainless steel for overlay welding such as a body portion of a continuous casting roll, and the overlay. The present invention relates to a metal member.

  In continuous casting, which is one of the manufacturing processes of steel products, cooling is performed by spraying cooling water while sandwiching and transporting steel that is continuously supplied from a tundish via a casting mold between multiple opposing continuous casting rolls. Is going. Rolls for continuous casting used in such processes are used in harsh environments where they are exposed to high-temperature steel or exposed to cooling water or its vapor, so heat resistance, corrosion resistance, wear resistance, etc. are required. It is done. Therefore, in general, a composite roll in which a build-up metal part made of 13Cr-4-8Ni martensitic stainless steel having excellent chemical and mechanical properties is given to the body part by overlay welding is used. It has been.

For example, Patent Document 1 discloses a filler material for overlay welding that gives such an overlay metal part. The filler material is mass%, C: 0.10 to 0.33%, Si: 0.2 to 0.5%, Mn: 0.5 to 2.0%, Ni: 0.5% or less, Co: 0.5 to 4.0%, Cr: 11.5 to 14.0%, Mo: 0.5 to 1.0%, Nb: 0.05 to 0.50%, V: 0.10 It has a component composition consisting of 0.30%, W: 0.3-1.0%, Cu: 0.5-2.0%, the balance Fe and inevitable impurities. That is, the amount of Ni added is reduced with respect to the 13Cr-4-8Ni alloy described above. Such a filler material is welded to the body of a continuous casting roll to form a weld overlay, and heat treatment is performed at a temperature range of 580 to 700 ° C., whereby high heat resistance and wear resistance are rolled. It can be granted to. As the main cause, it is stated that by reducing the amount of Ni added, the Ac ₁ point is raised, the high self-transformation stress is reduced, and the destruction of the anticorrosive film on the surface layer due to thermal fatigue cracks can be suppressed.

  Patent Document 2 discloses a filler material having a component composition in which the addition amount of Cr is increased and the addition amount of Ni is reduced with respect to the 13Cr-4 to 8Ni alloy. That is, the filler material is mass%, C: 0.15-0.25%, Si: 0.2-1.0%, Mn: 0.5-2.0%, Ni: 0.5% Hereinafter, Co: 0.5 to 3.0%, Cr: 15.0 to 18.0%, Mo: 0.5 to 1.0%, Nb: 0.05 to 0.5%, V: 0.00. It has a component composition consisting of 1 to 0.5%, W: 0.3 to 1.0%, Cu: 0.5 to 2.0%, the balance Fe and inevitable impurities. Even in such a filler metal, overlay welding is performed on the body of the continuous casting roll to form an overlay weld, and heat treatment is performed in a temperature range of 580 to 700 ° C., so that the roll has high heat resistance and corrosion resistance. Trying to give. The main reason for this is that Cr is added in excess of the amount required for carbide formation to form a solid solution, forming a passive state due to oxidation during use of the roll, and reducing the amount of Ni added. In addition to suppressing self-transformation stress as in Reference 1, it describes that the martensite phase can be refined while reducing the austenite region and suppressing the formation of elongated γ grains.

  In any case, in the filler metal disclosed in Patent Documents 1 and 2, after the overlay welding, a build-up forming portion having a hard and poor tough martensite phase as a main structure is provided. By tempering, the hardness and toughness required as a continuous casting roll are secured.

JP-A-7-173578 JP 2010-196108 A

  By the way, in the build-up member provided with the build-up forming portion mainly composed of the martensite phase as described above, heat treatment after welding is achieved by having both relatively high toughness and hardness even after welding. Can be omitted and the productivity can be improved.

  The present invention has been made in view of such circumstances, and an object of the present invention is to build up a built-up metal part having relatively high toughness and hardness without performing heat treatment after welding. It is providing the metal member and the filler material which can give this build-up metal part.

  The build-up metal member according to the present invention is a build-up metal member including a build-up metal part provided by build-up welding of a filler material, and the build-up metal part is in mass%, and C: 0. 03 to 0.10%, Si: 0.1 to 1.6%, Mn: 0.1 to 1.6%, Ni: 3.0 to 6.0%, Cr: 11.0 to 18.0% And W: 2.0 to 5.0%, and further O: 0.05% or less, and made of martensitic stainless steel having a composition composed of the balance Fe and inevitable impurities. It is characterized by.

  According to this invention, since the built-up metal member includes the built-up metal portion having both relatively high toughness and hardness without being subjected to heat treatment after welding, the productivity is high and the durability is excellent while being inexpensive. .

  In the above-described invention, the build-up metal part may further include Nb: within a range of 0.1 to 1.0%. According to this invention, since the built-up metal member includes the built-up metal portion having higher toughness without being subjected to heat treatment after welding, the productivity is high and the durability is excellent while being inexpensive.

  In the above-described invention, the build-up metal part may further include at least one of Mo: 0.1 to 3.0% and V: 0.1 to 0.5%. It is good. According to this invention, since the built-up metal member includes the built-up metal part having high high-temperature hardness without being subjected to heat treatment after welding, it is therefore excellent in durability while being high in productivity and inexpensive.

  In the above-described invention, the build-up metal part may be composed of a plurality of layers. According to this invention, the built-up metal member includes the built-up metal portion having both higher toughness and hardness without being subjected to heat treatment after welding, and particularly has high toughness and hardness in the surface layer portion of the built-up metal portion. Therefore, it is excellent in durability while being high in productivity and inexpensive.

  In the above-described invention, the build-up metal member is a continuous casting roll. According to this invention, the built-up metal member is a continuous casting roll used in a harsh environment, and therefore has high productivity and low cost but excellent durability.

  The filler material according to the present invention is a filler material for overlay welding of powder made of martensitic stainless steel, and as an essential additive element in mass%, C: 0.06 to 0.15%, Si : 0.1-1.7%, Mn: 0.1-1.7%, Ni: 3.0-6.0%, Cr: 11.0-18.0%, and W: 2.0 It is characterized by being a metal powder comprising -5.0% and further containing O: 0.08% or less as an optional additive element, the balance being Fe and inevitable impurities.

  According to this invention, although it is a metal powder that is overlay welded with decarburization, it provides a built-up metal portion having both relatively high toughness and hardness without performing heat treatment after welding, and thus in productivity. It is possible to provide a built-up metal member that is high in cost and excellent in durability.

  The filler material according to the present invention is a filler material for overlay welding of a linear body made of martensitic stainless steel, and as an essential additive element in mass%, C: 0.03 to 0.10%, Si: 0.1 to 1.7%, Mn: 0.1 to 1.7%, Ni: 3.0 to 6.0%, Cr: 11.0 to 18.0%, and W: 2. It is characterized by being a metal linear body comprising 0 to 5.0%, further containing O: 0.02% or less as an optional additive element, and the balance being Fe and inevitable impurities.

  According to this invention, it is a linear body that is easy to handle, and gives a built-up metal part that has both relatively high toughness and hardness without being subjected to heat treatment after welding, and thus is highly productive and inexpensive but durable. Therefore, it is possible to provide a built-up metal member having excellent properties.

  In the above-described invention, the build-up metal part may further include Nb: within a range of 0.1 to 1.0%. According to this invention, even if it does not heat-process after welding, the build-up metal part which has still higher toughness can be given, and since it is high in productivity, it can give the build-up metal member excellent in durability though it is cheap.

  In the above-described invention, the optional additive element may include Mo: 0.1 to 3.0% and V: 0.1 to 0.5%. According to this invention, it is possible to provide a built-up metal part having high high-temperature hardness without being subjected to heat treatment after welding, and therefore, it is possible to provide a built-up metal member that is highly productive and inexpensive but more durable.

It is the (a) perspective view and (b) sectional drawing of the principal part of the roll for continuous casting which is the build-up metal member by this invention. It is a perspective view of a test piece. It is a figure which shows the component composition of the Example of a filler material for welding (metal powder) and a comparative example. It is a figure which shows the component composition of the Example of a filler material for welding (metal wire) and a comparative example. It is a figure which shows the component composition and test result of the overlay welding part of an Example and a comparative example. It is a figure which shows the component composition and test result of the overlay welding part of an Example and a comparative example.

  As one embodiment of the built-up metal member according to the present invention, a continuous casting roll used in continuous casting in a manufacturing process of steel products will be described.

  As shown to Fig.1 (a), the roll 1 for continuous casting consists of the substantially cylindrical roll main body 2, and the axial part 3 which protrudes toward a longitudinal direction outward from the both sides. As shown in FIG. 2B, on the outer surface of the core portion 20 of the roll body 2, a plurality of built-up layers 21, that is, a first built-up layer 21a and a second built-up layer are formed. 21b and a third built-up layer 21c are provided. The details of the welding filler material and construction for providing the overlay layer 21 will be described later.

  Next, a test piece 4 imitating the roll body 2 (see FIG. 1) of the continuous casting roll 1 as shown in FIG. 2 was prepared, and various tests were performed. That is, using the welding filler material made of metal powder having the component composition shown in FIG. 3 and the welding filler material made of metal wire having the component composition shown in FIG. A test piece 4 in which a build-up weld 41 is formed by overlay welding on multiple layers is provided for various tests.

  Specifically, a substantially rectangular parallelepiped welded specimen 40 having a thickness of 9 mm, a width of 100 mm, and a length of 200 mm made of JIS SUS410 is prepared. Using this welding test piece 40, welding welding material made of metal powder and welding filler material made of metal wire (linear body) were subjected to overlay welding under the following welding conditions, A prime weld 41 is provided.

  First, using a welding filler material made of a metal powder having the composition shown in FIG. 3 manufactured by the gas atomization method, PTA (Plasma Transferred Arc) welding is performed on one surface of the test piece 40 to be welded. Three-layer overlay welding is performed.

  In PTA welding, Ar is used for the powder carrier gas, plasma gas and shield gas, the supply amounts thereof are 3.0, 1.2 and 14.0 L / min, the welding current is 150 A, the arc voltage is 27 V, the powder The supply amount is set to 12 g / min, the tip-base metal distance is 10 mm, the welding speed is 40 mm / min, the weaving is 8 mm in width, and the number of times is 2 Hz. Here, the temperature between passes was 150 ° C. or less, the number of passes in the first layer was 22, the number of passes in the second layer was 21, and the number of passes in the third layer was 20. In order to prevent the base metal from being melted into the build-up weld, two layers of buttering are performed with a welding filler material used for welding before the first build-up welding.

  On the other hand, using a welding filler metal made of a metal wire having the composition shown in FIG. 4, MAG (Metal Arc Gas) welding is performed on one surface of the welded test piece 40 by three-layer overlay welding. Do.

  The welding filler metal made of metal wire is hot forged, rolled and drawn on a 50 kg steel ingot obtained using a vacuum high-frequency melting furnace, and has a diameter of 1.2 mm having the component composition shown in FIG. Finished with metal wire.

MAG welding uses a mixed gas of Ar 80% + CO ₂ 20% as the shielding gas, the supply amount is set to 15.0 L / min, the welding current is set to 150 A, the arc voltage is set to 21 V, and the tip-base metal distance is 15 mm. The welding speed is 300 mm / min. Here, the number of passes in the first layer was 13, the number of passes in the second layer was 12, and the number of passes in the third layer was 11. Similarly to the above-described PTA welding, two layers of buttering are performed with a filler material used for welding before the first overlay welding in order to prevent the base metal from being melted into the overlay welding portion.

  One test piece used for the Vickers hardness test and composition analysis test and one test piece 3 used for the Charpy impact test were cut out from the build-up welded portion 41 of each test piece 4 after welding. The cutout position was set as a surface layer portion of the build-up welded portion 41 as much as possible.

  In the Vickers hardness test, a commercially available Vickers hardness tester was used, and three points were measured at room temperature and 600 ° C., and the average value was taken as the measured value. In the component composition test, the test piece after the Vickers hardness test was chemically analyzed to identify the component composition. Moreover, the Charpy impact test measured 3 times at room temperature using the commercially available Charpy impact test apparatus, and made the average value the measured value. The obtained test results are summarized in FIGS.

  First, the test results of Examples 1 to 6 and Comparative Examples 1 to 15 obtained using a welding filler material made of metal powder will be described with reference to FIG.

In Examples 1 to 6, the impact value was 48 to 78 J / cm ² , the room temperature hardness was 335 to 384 Hv, and the high temperature (600 ° C.) hardness was 190 to 242 Hv. That is, the build-up weld portion 41 is not subjected to heat treatment after welding, but is relatively as large as a build-up metal portion made of 13Cr-4-8Ni martensitic stainless steel provided by performing a conventional heat treatment. It has both high toughness and hardness.

In detail, compared with Example 1, in Comparative Example 1 with a small C content, the impact value hardly changed, but the room temperature hardness decreased to 221 Hv. On the other hand, compared with Example 1, in Comparative Example 2 having a large C content, the room temperature hardness and the high temperature hardness were hardly changed, but the impact value was reduced to 25 J / cm ² . In Comparative Example 1, the martensite phase is not sufficiently generated, and in Comparative Example 2, it is considered that the carbide segregates at the grain boundaries and lowers the toughness.

Compared to Example 1, in Comparative Example 3 having a low Si content, the room temperature hardness and the high temperature hardness remained almost the same, but the impact value decreased to 22 J / cm ² . On the other hand, compared with Example 1, in Comparative Example 4 having a large Si content, similarly, although the room temperature hardness and the high temperature hardness remained almost the same, the impact value decreased to 32 J / cm ² . In Comparative Example 3, it is considered that deoxidation by Si was insufficient and an oxide was generated.

Compared to Example 1, in Comparative Example 5 having a low Mn content, the room temperature hardness and the high temperature hardness remained almost unchanged, but the impact value decreased to 13 J / cm ² . On the other hand, compared with Example 1, also in Comparative Example 6 having a large Mn content, the impact value decreased to 38 J / cm ² although the room temperature hardness and the high temperature hardness were hardly changed. In Comparative Example 5, it is considered that deoxidation by Mn was insufficient and the oxide was purified.

Compared to Example 1, in Comparative Example 7 with a low Ni content, the impact value, room temperature hardness, and high temperature hardness were 15 J / cm ² , 274 Hv, and 121 Hv, respectively, which are all reduced. On the other hand, compared with Example 1, in Comparative Example 8 having a large Ni content, although the impact value hardly changed, the room temperature hardness and the high temperature hardness decreased to 288 Hv and 156 Hv, respectively. In Comparative Example 7, it is considered that the ferrite phase increased and the martensite phase was not sufficiently generated. On the other hand, in Comparative Example 8, it is considered that the retained austenite phase was excessive.

  Compared to Example 1, in Comparative Example 9 where the Cr content is large, the impact value hardly changes, but the room temperature hardness and the high temperature hardness are reduced to 270 Hv and 165 Hv, respectively. In Comparative Example 9, it is considered that quenching was insufficient due to the stable ferrite phase, and the martensite phase was not sufficiently generated.

Compared to Example 1, in Comparative Example 10 having a small W content, the room temperature hardness and the high temperature hardness hardly change, but the impact value is reduced to 28 J / cm ² . On the other hand, compared with Example 1, in Comparative Example 11 having a large W content, the room temperature hardness and the high temperature hardness remained almost the same, but the impact value decreased to 35 J / cm ² . In Comparative Example 10, it is considered that the carbide of W cannot be sufficiently generated during solidification, and the crystal structure of the built-up weld that should be refined as a crystal nucleus is coarsened. On the other hand, in Comparative Example 11, it is considered that W carbide was excessively generated.

Compared to Example 1, in Comparative Example 12 with a large content of O, the room temperature hardness and the high temperature hardness hardly change, but the impact value is reduced to 27 J / cm ^{2. In} Comparative Example 12, the oxide is oxide. Is considered to be overgenerated.

Compared to Example 1, in Comparative Example 13 where the Nb content is large, the room temperature hardness and the high temperature hardness are almost the same, but the impact value is reduced to 20 J / cm ² . In Comparative Example 13, it is considered that the carbide of Nb was precipitated at the grain boundaries to reduce the impact value.

Compared to Example 1, in Comparative Example 14 having a large Mo content, the room temperature hardness and the high temperature hardness remained almost the same, but the impact value decreased to 21 J / cm ² . In Comparative Example 14, it is considered that Mo carbides precipitated at the grain boundaries and lowered the impact value.

Compared to Example 1, in Comparative Example 15 having a large V content, the room temperature hardness and the high temperature hardness hardly change, but the impact value is reduced to 25 J / cm ² . In Comparative Example 15, it is considered that the carbide of V was precipitated at the grain boundary and lowered the impact value.

Next, in Example 2, the impact value was 49 J / cm ² , the room temperature hardness was 335 Hv, and the high temperature hardness was 190 Hv. Compared to Example 2, in Example 3 in which Nb was added, the room temperature hardness was as high as 347 Hv, the high temperature hardness was as high as 201 Hv, and the impact value was particularly high as 78 J / cm ² . Nb combines with C to produce fine carbides, which are used as solidification nuclei to refine the crystal structure of the weld overlay and increase the impact value.

Compared to Example 2, in Examples 4 to 6 to which Mo or V was added, although the impact value was almost the same as 48 to 53 J / cm ² , the room temperature hardness was 350 to 371 Hv, and the high temperature hardness was 218 to 238 Hv. high. It is considered that Mo and V combine with C to generate carbides, and improve room temperature hardness and high temperature hardness.

Incidentally, with respect to Example 2, Nb, in Example 1 were added Mo and V, impact value 75 J / cm ^2, room temperature hardness 384Hv, high-temperature hardness is higher both with 242Hv. From this, it is considered that Nb improves the impact value, and Mo and V improve the room temperature hardness and the high temperature hardness, as described above.

  That is, in Examples 1 to 6, compared to Comparative Examples 1 to 15, both high toughness and hardness are achieved in the overlay weld. On the other hand, the filler metal for welding which consists of metal powder which gives the overlay welding part of the component composition shown in FIG. 5 has the component composition shown in FIG.

  Referring to FIGS. 3 and 5, in Examples 1 to 6, the contents of Si and Mn are 0.93 to 0.97% and 0.98 to 1.02%, respectively, for the filler metal for welding. On the other hand, in the build-up weld zone, both 0.83 to 0.86% and 0.89 to 0.92% are lowered after welding. It is considered that the build-up weld was deoxidized during welding by Si and Mn, and decreased with this.

  On the other hand, in Examples 1 to 6, the component compositions of C and O were 0.07 to 0.09% and 0.054 to 0.058% for the filler metal for welding, respectively, but overlaying In the welded portion, both 0.05 to 0.07% and 0.029 to 0.038% decreased after welding. It is considered that decarburization occurred in the overlay weld during welding, and the C content was reduced accordingly. Furthermore, in addition to this decarburization, the above-described deoxidation by Si and Mn also occurs, and it is considered that the content of O in the build-up weld has decreased.

  As described above, the built-up welds of Examples 1 to 6 have both relatively high toughness and hardness without performing heat treatment after welding. This is because the content of C is reduced (see Comparative Example 2) to moderately suppress the formation of the martensite phase and further the content of W is increased (see Comparative Example 10) to become solidification nuclei. It is considered that a large amount of carbide was generated and the crystal grains of the structure of the overlay weld were refined.

  Next, the test results of Examples 7 to 12 and Comparative Examples 16 to 30 obtained using the welding filler material made of metal wire will be described with reference to FIG.

In the build-up welds of Examples 7 to 12, the impact value was 48 to 70 J / cm ² , the room temperature hardness was 331 to 370 Hv, and the high temperature hardness was 191 to 240 Hv. That is, the build-up weld portion 41 is not subjected to heat treatment after welding, but is relatively as large as a build-up metal portion made of 13Cr-4-8Ni martensitic stainless steel provided by performing a conventional heat treatment. It has both high toughness and hardness.

In detail, compared with Example 7, in Comparative Example 16 with a small C content, the impact value hardly changed, but the room temperature hardness decreased to 211 Hv. On the other hand, in Comparative Example 17 in which the C content was higher than that in Example 7, the room temperature hardness and the high temperature hardness were hardly changed, but the impact value was reduced to 25 J / cm ² . In Comparative Example 16, the martensite phase is not sufficiently generated, and in Comparative Example 17, it is considered that carbides are precipitated at the grain boundaries to reduce toughness.

Compared to Example 7, in Comparative Example 18 having a small Si content, the room temperature hardness and the high temperature hardness hardly change, but the impact value is reduced to 20 J / cm ² . On the other hand, compared with Example 7, also in Comparative Example 19 having a large Si content, the room temperature hardness and the high temperature hardness hardly changed, but the impact value decreased to 28 J / cm ² . In Comparative Example 18, it is considered that deoxidation by Si was insufficient and oxide was excessively generated.

Compared to Example 7, in Comparative Example 20 with a low Mn content, the room temperature hardness and the high temperature hardness are almost the same, but the impact value is reduced to 15 J / cm ² . On the other hand, compared with Example 7, in Comparative Example 21 having a high Mn content, the impact value is reduced to 35 J / cm ² although the room temperature hardness and the high temperature hardness are hardly changed. In Comparative Example 20, it is considered that deoxidation by Mn was insufficient and oxide was excessively generated.

Compared to Example 7, in Comparative Example 22 with a low Ni content, the impact value, room temperature hardness, and high temperature hardness were reduced to 18 J / cm ² , 268 Hv, and 131 Hv, respectively. On the other hand, compared with Example 7, in Comparative Example 23 with a large Ni content, although the impact value is not significantly changed, the room temperature hardness and the high temperature hardness are reduced to 291 Hv and 166 Hv, respectively. In Comparative Example 22, it is considered that the ferrite phase increased and the martensite phase was not sufficiently generated. On the other hand, in Comparative Example 23, it is considered that the retained austenite phase was excessive.

  In contrast to Example 7, in Comparative Example 24 where the Cr content is large, the impact value is not much changed, but the room temperature hardness and the high temperature hardness are reduced to 255 Hv and 135 Hv, respectively. In Comparative Example 24, it is considered that the stable ferrite phase caused insufficient quenching, and the martensite phase was not sufficiently generated.

Compared to Example 7, in Comparative Example 25, in which the W content is small, the room temperature hardness and the high temperature hardness are not significantly changed, but the impact value is reduced to 25 J / cm ² . On the other hand, compared with Example 7, in Comparative Example 26 having a large W content, the room temperature hardness and the high temperature hardness are not significantly changed, but the impact value is reduced to 32 J / cm ² . In Comparative Example 25, it is considered that the carbide of W cannot be sufficiently generated during solidification, and the crystal structure of the overlay weld that should be refined as a crystal nucleus has been coarsened. On the other hand, in Comparative Example 26, it is considered that W carbide was excessively generated.

In contrast to Example 7, in Comparative Example 27 with a large O content, the room temperature hardness and the high temperature hardness were not significantly changed, but the impact value was reduced to 25 J / cm ² . In Comparative Example 27, it is considered that an oxide was excessively generated.

Compared to Example 7, in Comparative Example 28 with a high Nb content, the room temperature hardness and the high temperature hardness were not significantly changed, but the impact value was reduced to 15 J / cm ² . In Comparative Example 28, it is considered that carbides of Nb were precipitated at the grain boundaries to reduce the impact value.

In contrast to Example 7, in Comparative Example 29 with a large Mo content, the room temperature hardness and the high temperature hardness did not change much, but the impact value decreased to 20 J / cm ² . In Comparative Example 29, it is considered that Mo carbides precipitated at the grain boundaries and lowered the impact value.

Compared to Example 7, in Comparative Example 30 with a low V content, the room temperature hardness and the high temperature hardness were not significantly changed, but the impact value was reduced to 20 J / cm ² . In Comparative Example 30, it is considered that V carbides precipitated at the grain boundaries and lowered the impact value.

Next, in Example 8, the impact value was 50 J / cm ² , the room temperature hardness was 331 Hv, and the high temperature hardness was 191 Hv. In contrast to Example 8, Nb-added Example 9 has a room temperature hardness of 342 Hv and a high temperature hardness of 198 Hv, and particularly an impact value of 70 J / cm ² . Nb combines with C to produce fine carbides, which are used as solidification nuclei to refine the crystal structure of the weld overlay and increase the impact value.

Compared to Example 8, in Examples 10 to 12 to which Mo or V was added, although the impact value was not much different from 48 to 50 J / cm ² , the room temperature hardness was 339 to 367 Hv, and the high temperature hardness was 211 to 240 Hv. high. It is considered that Mo and V combine with C to generate carbides, and improve room temperature hardness and high temperature hardness.

In Example 7, in which Nb, Mo, and V are added to Example 8, the impact value is 65 J / cm ² , the room temperature hardness is 370 Hv, and the high temperature hardness is 232 Hv. Similarly to the above, it is considered that Nb improved the impact value, and Mo and V improved room temperature hardness and high temperature hardness.

  In other words, it can be said that Examples 7 to 12 have both high toughness and hardness in the overlay welded part as compared with Comparative Examples 16 to 30. On the other hand, the filler metal for welding which consists of the metal wire which gives the overlay welding part of such a component composition shown in FIG. 6 has the component composition shown in FIG.

  4 and 6, in Examples 7 to 12, the contents of Si and Mn are 0.94 to 1.04% and 0.92 to 1.08% in the filler metal for welding, respectively. On the other hand, in the overlay welded portion, both 0.85 to 0.93% and 0.85 to 1.00% are lowered after welding. It is considered that the build-up weld was deoxidized by Si and Mn during welding, and decreased along with this.

  On the other hand, in Examples 7 to 12, the contents of C and O are 0.05 to 0.06% and 0.009 to 0.012% in the filler metal for welding, respectively, but overlay welding In the part, 0.07 to 0.08% and 0.033 to 0.040%, both increased after welding. Although deoxidation occurs in the build-up weld due to the above-described Si and Mn, oxidation due to the heat of build-up welding also occurs, and it is considered that the O content as a whole has increased.

  As described above, the built-up welds of Examples 7 to 12 have relatively high toughness and hardness without performing heat treatment after welding. This is because the content of C is reduced (see Comparative Example 17) to moderately suppress the formation of the martensite phase, and the content of W is further increased (see Comparative Example 25) to become solidification nuclei. It is considered that a large amount of carbide was generated and the crystal grains of the structure of the overlay weld were refined.

  Moreover, as mentioned above, when the welding filler material which consists of metal wires is used, content of O of the build-up welding part will increase by oxidation. On the other hand, when a filler metal for welding made of metal powder is used, the contents of C and O in the overlay welded portion decrease due to decarburization. Compared to metal wires, metal powder has a large surface area per weight and is considered to be easily decarburized. Therefore, it can be seen that the contents of C and O should be adjusted according to the shape of the filler metal for welding in order to obtain an overlay weld of the same component composition as in Examples 1 to 12 described above.

  As described above, welding welding material made of metal powder or metal wire (linear body) is used, and overlay welding is performed on the outer peripheral surface of the core portion 20 of the continuous casting roll, and heat treatment is not performed after welding. However, it is possible to provide a continuous casting roll 1 that has a relatively high toughness and hardness on the surface of the roll main body 2 to provide a continuous casting roll 1 that is inexpensive and excellent in durability because of its high productivity (see FIG. 1). That is, the continuous casting roll 1 provided with the build-up layer 21 having the component composition shown in FIGS. 5 and 6 is high in productivity and is therefore excellent in durability while being inexpensive.

  Next, in obtaining a built-up weld portion equivalent to the above-described embodiment, the component range of the essential additive element as a welding filler material made of metal powder or metal wire, and the component of the contained element as the build-up weld portion The reason for defining the range will be described.

  C is an element added to promote the formation of the martensite phase and increase the hardness. On the other hand, when C is excessive, grain boundary carbides are generated and the toughness is lowered. Therefore, the content of C in the build-up weld is mass% and is in the range of 0.03 to 0.10%. For the same reason, the amount of addition of C in the welding filler metal made of a metal wire is in the range of 0.03 to 0.10% in mass%. On the other hand, since decarburization is performed when overlay welding is performed with metal powder, the amount of C added to the filler metal for welding made of metal powder is in a range of 0.06 to 0.15% in mass%.

  Si promotes deoxidation of the steel, but on the other hand it reduces toughness if included in excess. Therefore, the Si content in the build-up weld is in mass% and is in the range of 0.1 to 1.6%. Further, since Si is a deoxidizer and its content is reduced by overlay welding, the amount of Si added to the welding filler material made of metal powder or metal wire is 0.1 to 1.% by mass. It is within the range of 7%.

  Mn promotes deoxidation of steel, but if it is excessively contained, it reduces toughness. Therefore, the content of Mn in the build-up weld zone is mass% and is in the range of 0.1 to 1.6%. Mn is a deoxidizer and its content is reduced by overlay welding. Therefore, the amount of Mn added to the filler metal for welding made of metal powder or metal wire is in mass% and is in the range of 0.1 to 1.7%.

  Ni generates a ferrite phase and lowers the room temperature hardness. On the other hand, when it is contained excessively, Ni increases the austenite phase and increases the occurrence of heat cracks. Therefore, the content of Ni in the build-up weld zone is in mass%, and is in the range of 3.0 to 6.0%. For the same reason, the addition amount of Ni in the welding filler material made of metal powder or metal wire is in the range of 3.0 to 6.0% by mass.

  Cr improves corrosion resistance and oxidation resistance, but on the other hand, if it is contained excessively, it increases the ferrite phase and decreases the hardness. Therefore, the Cr content in the weld overlay is mass% and is in the range of 11.0 to 18.0%. For the same reason, the addition amount of Cr in the welding filler material made of metal powder or metal wire is in the range of 11.0 to 18.0% in mass%.

  W generates carbides and refines the structure to increase the toughness. On the other hand, if contained in excess, the carbide increases the carbides and decreases the toughness. Therefore, the content of W in the build-up weld is mass% and is in the range of 2.0 to 5.0%. For the same reason, the addition amount of W in the welding filler material made of metal powder or metal wire is in mass% and is in the range of 2.0 to 5.0%.

  Furthermore, the reason for determining the component range of the arbitrarily added element as the filler metal for welding made of metal powder or metal wire and the component range of the contained element as the build-up weld will be described.

  If O is contained excessively, it reduces toughness. Therefore, the content of O in the build-up weld is in mass% and is in the range of 0.05% or less. When build-up welding is performed using a welding filler metal made of metal wire, oxidation occurs and the content of O in the build-up weld increases. Therefore, the amount of O added to the welding filler metal made of metal wire is in mass% and is in the range of 0.02% or less. On the other hand, when overlay welding is performed using a welding filler material made of metal powder, the content of O in the overlay weld decreases with decarburization. Therefore, the amount of O added to the welding filler material made of metal powder is in mass% and is in the range of 0.08% or less.

  Nb produces fine carbides and refines the structure of the weld overlay, but if excessively contained, carbides are produced in a continuous manner and lower the mechanical strength. Therefore, the content of Nb in the build-up weld is in mass% and is in the range of 0.1 to 1.0%. For the same reason, the amount of Nb added to the welding filler material made of metal powder or metal wire is in mass% and is in the range of 0.1 to 1.0%.

  Mo produces carbides and increases the high-temperature strength. On the other hand, if it is excessively contained, it reduces toughness. Therefore, the content of Mo in the build-up weld zone is mass% and is in the range of 0.1 to 3.0%. For the same reason, the amount of Mo added to the welding filler material made of metal powder or metal wire is in mass% and is in the range of 0.1 to 3.0%.

  V, like Mo, generates carbides and increases the high-temperature strength. On the other hand, when V is contained excessively, it decreases toughness and ductility. Therefore, the content of V in the build-up weld is mass%, and is in the range of 0.1 to 0.5%. For the same reason, the addition amount of V in the filler metal for welding made of metal powder or metal wire is in mass% and is in the range of 0.1 to 0.5%.

  Up to this point, the representative embodiments according to the present invention and the modifications based thereon have been described, but the present invention is not necessarily limited thereto. Those skilled in the art will recognize a variety of alternative embodiments and modifications without departing from the scope of the appended claims.

DESCRIPTION OF SYMBOLS 1 Roll for continuous casting 4 Test piece 40 Welded test piece 41 Overlay welding part

Claims (9)

A build-up metal member including a build-up metal part given by build-up welding of a filler material,
The overlay metal part is mass%,
C: 0.03-0.10%,
Si: 0.1 to 1.6%,
Mn: 0.1 to 1.6%,
Ni: 3.0-6.0%,
Cr: 11.0-18.0%, and
W: 2.0 to 5.0% included,
O: A built-up metal member comprising 0.05% or less of martensitic stainless steel having a composition composed of the remaining Fe and inevitable impurities. Furthermore, the overlay metal part is
The build-up metal member according to claim 1, which may be contained within a range of Nb: 0.1 to 1.0%. Furthermore, the overlay metal part is
Mo: 0.1 to 3.0%,
The build-up metal member according to claim 1, wherein at least one of the V may be contained within a range of 0.1 to 0.5%.   4. The built-up metal member according to claim 1, wherein the built-up metal portion is composed of a plurality of layers.   The build-up metal member according to claim 1, wherein the build-up metal member is a continuous casting roll. A filler material for overlay welding of powder made of martensitic stainless steel,
As an essential additive element,
C: 0.06 to 0.15%,
Si: 0.1 to 1.7%,
Mn: 0.1 to 1.7%,
Ni: 3.0-6.0%,
Cr: 11.0-18.0%, and
W: 2.0-5.0% included,
Furthermore, as an optional additive element,
O: A filler metal which may contain 0.08% or less and is a metal powder composed of the remainder Fe and inevitable impurities. It is a filler metal for overlay welding of a linear body made of martensitic stainless steel,
As an essential additive element,
C: 0.03-0.10%,
Si: 0.1 to 1.7%,
Mn: 0.1 to 1.7%,
Ni: 3.0-6.0%,
Cr: 11.0-18.0%, and
W: 2.0-5.0% included,
Furthermore, as an optional additive element,
O: A filler material, which may contain 0.02% or less, and is a metal linear body composed of the remaining Fe and inevitable impurities. As the optional additive element,
The filler material according to claim 6 or 7, wherein Nb may be contained within a range of 0.1 to 1.0%. As the optional additive element,
Mo: 0.1 to 3.0%,
V: Filler material according to one of claims 6 to 8, characterized in that it can contain at least one in each range of 0.1 to 0.5%.