CN100500918C

CN100500918C - Steel for large diameter non-tempering petroleum sleeve

Info

Publication number: CN100500918C
Application number: CNB2007100487667A
Authority: CN
Inventors: 陈坤; 尹人洁; 刘建中; 易兴俊
Original assignee: Pangang Group Chengdu Iron & Steel Co Ltd
Current assignee: Pangang Group Chengdu Iron & Steel Co Ltd
Priority date: 2007-03-29
Filing date: 2007-03-29
Publication date: 2009-06-17
Anticipated expiration: 2027-03-29
Also published as: CN101054650A

Abstract

The invention discloses a big-caliber non-tempered and quenched steel for oil bushing. The steel is composed of the following components in percentage: C 0.38-0.45%, Si 0.40-0.60%, Mn 1.50-1.70%, V 0.08-0.12%, Nb 0.03-0.05% and Ti 0.01-0.15%. The beneficial effects of the invention reside in adding in combination in Nb, V and Ti which have strong crystal granules precipitation, strengthening and refining ability and improve the strength, roughness and rigidity of the steel and adding in Al as alloying element and deoxidization element which satisfies the demand of high rigidity and impact roughness for producing big-caliber non-tempered and quenched steel for oil bushing.

Description

Steel for large diameter non-tempering petroleum sleeve

Technical field

The present invention relates to oil casing pipe steel, particularly a kind of steel for large diameter non-tempering petroleum sleeve.

Background technology

Middle carbon microalloy pearlitic steel is to add micro alloying element in medium carbon steel and medium carbon manganese steel, by the process means of controlled rolling and controlled cooling, makes its precipitation strength and crystal grain thinning and improves intensity, hardness and toughness, reaches the performance level of quenched and tempered steel.Because of having omitted the modifier treatment operation, this novel steel grade is compared with quenched and tempered steel, can make total manufacturing cost reduce more than 15%.Therefore, develop economic environment-friendly type new steel grade that can satisfy the demand without modifier treatment, that obdurability is good after the hot rolling, have important in theory meaning and actual application value.

At present, the production of non-tempering petroleum casing steel is normally added micro alloying element in medium carbon steel and medium carbon manganese steel, but often only adds a kind of micro alloying element.Normally add V, improving the intensity of its online normalizing, as steel grade 35Mn2V, 38Mn6V, 33Mn2V, 36Mn2V, 42MnMo7,34Mn2VN, 42Mn2V and the 37Mn2V etc. of the microalloy non-quenched and tempered N 80 level petroleum casing pipe of domestic-developed.Owing to only add a kind of micro alloying element, the raising of steel grade impelling strength is limited, so these steel grades can not satisfy in producing large diameter non-tempering petroleum sleeve pipe process the requirement that high strength and impelling strength are complementary.

Summary of the invention

Technical problem to be solved by this invention provides a kind of steel for large diameter non-tempering petroleum sleeve, and this steel grade can satisfy in producing large diameter non-tempering petroleum sleeve pipe process the requirement that high strength and impelling strength are complementary preferably.

The technical solution adopted for the present invention to solve the technical problems is: steel for large diameter non-tempering petroleum sleeve of the present invention, this steel is made up of following ingredients by weight percentage: C 0.38～0.45%, Si 0.40～0.60%, Mn 1.50～1.70%, V 0.08～0.12%, Nb 0.03～0.05%, Ti 0.01～0.15%, Al 0.02～0.05%, all the other are Fe and impurity.

In above-mentioned preferred version, P in the described impurity≤0.025%, S≤0.020%.

In above-mentioned preferred version, the carbon equivalent Ceq. of this steel is 0.66～0.75%, carbon equivalent Ceq.=C+Mn/6+V/5.

The invention has the beneficial effects as follows, unite and add ability Nb, V, Ti with stronger precipitation strength and crystal grain thinning, improve intensity, hardness and the toughness of steel grade, and Al introduced as alloy element and deoxidant element, can satisfy in producing large diameter non-tempering petroleum sleeve pipe process the requirement that high strength and impelling strength are complementary preferably.

Description of drawings

This specification sheets comprises following four width of cloth accompanying drawings:

Fig. 1 is the metallographic structure figure of steel for large diameter non-tempering petroleum sleeve of the present invention;

Fig. 2 is the metallographic structure figure of steel for large diameter non-tempering petroleum sleeve of the present invention;

Fig. 3 is the division and the numbering synoptic diagram of steel for large diameter non-tempering petroleum sleeve pulling force sample of the present invention;

Fig. 4 is a steel for large diameter non-tempering petroleum sleeve pulling force sample detected result graphic representation of the present invention.

Embodiment

The present invention is further described below in conjunction with drawings and Examples.

Steel for large diameter non-tempering petroleum sleeve of the present invention, this steel is made up of following ingredients by weight percentage: C 0.38～0.45%, Si 0.40～0.60%, Mn 1.50～1.70%, V 0.08～0.12%, Nb 0.03～0.05%, Ti 0.01～0.15%, Al 0.02～0.05%, all the other are Fe and impurity.

Because Nb, V, Ti have the stronger precipitation strength and the ability of crystal grain thinning, unite the effective of a kind of micro alloying element of the more single adding of the effect that adds multiple micro alloying element, can obtain perlite+ferrite metallographic structure, its Medium pearlite percentage composition reaches 80～90%, so can improve intensity, hardness and the toughness of steel grade, make it to satisfy preferably in producing large diameter non-tempering petroleum sleeve pipe process the requirement that high strength and impelling strength are complementary.

Referring to Fig. 1 and Fig. 2, metallographic structure is ferrite+perlite, and crystal grain tiny (10.0 grades of grain fineness numbers), and homogeneous microstructure satisfy the non-hardened and tempered steel performance requriements fully.

As a preferred embodiment of the present invention, this steel is made up of following ingredients by weight percentage: C0.38～0.45%, Si 0.40～0.60%, Mn 1.50～1.70%, V 0.08～0.12%, Nb0.03～0.05%, Ti 0.01～0.15%, Al 0.02～0.05%, all the other are Fe and impurity, be Al not only as deoxidant element, and add in the steel with alloy element.

In above-mentioned preferred version, the carbon equivalent Ceq. of this steel is 0.66～0.75%, Ceq.=C+Mn/6+V/5.

Al is as alloying element, and its content is controlled in strictness.

Embodiment:

1. smelting composition

Each embodiment smelts composition such as following table:

Heat (batch) number	C	Si	Mn	V	Nb	Ti	Al	P	S
Heat (batch) number	C	Si	Mn	V	Nb	Ti	Al	P	S	0683613	0.38	0.35	1.68	0.12	0.031	0.014	0.044	0.018	0.012
0683634	0.40	0.42	1.62	0.10	0.037	0.025	0.030	0.016	0.011	0683613	0.38	0.35	1.68	0.12	0.031	0.014	0.044	0.018	0.012
0683634	0.40	0.42	1.62	0.10	0.037	0.025	0.030	0.016	0.011	0683636	0.44	0.57	1.52	0.082	0.049	0.045	0.022	0.017	0.010

2. smelting operation

In steel-making, casting process, operation, Working Procedure Controlling are carried out in strict accordance with standard, make the chemical ingredients of steel even, to guarantee the performance of steel pipe.

The T[O of strand] amount: 20～35PPm, casting blank foreign matter total amount: 80～110PPm.

Steel pipe finished product chemical ingredients permissible variation meets the regulation of table 2 among the GB/T222.1984.

3. steel pipe rolling

In the operation of rolling, rationally formulate various processing parameters such as rolling rhythm, hollow forging charging temperature, hollow forging tapping temperature, reheating furnace stepping period, speed of cooling, to satisfy its performance index.Main processing parameter is as follows:

The ring furnace furnace temperature must guarantee the steel temperature of coming out of the stove: 1230 ± 20 ℃;

Adopt online normalizing process, go into 500～600 ℃ of walking-beam furnace steel temperature;

The walking-beam furnace furnace temperature must guarantee the steel temperature of coming out of the stove: 920 ± 20 ℃;

Rolling rhythm: Φ 244.5 〉=60 seconds, Φ 339.7 〉=70 seconds, walking-beam furnace is by the tooth cloth;

Adopt cooling fast behind the sizing.

4. steel tube performance detects

Steel tube performance detected result such as following table:

5, along steel pipe circumferential direction Performance Detection

For detecting steel pipe performance variation situation along the circumferential direction, 300mm long tube ring is got in the pup joint end, by 16 pulling force samples, the number consecutively of getting shown in Figure 3.

Detected result as shown in Figure 4, except that No. 3 samples more unusually, the curve that all the other 15 samples are formed is more smooth, illustrates that the steel pipe radial performance is more even.

Claims

1. steel for large diameter non-tempering petroleum sleeve, it is characterized in that: this steel is made up of following ingredients by weight percentage: C 0.38～0.45%, Si 0.40～0.60%, Mn 1.50～1.70%, V 0.08～0.12%, Nb 0.03～0.05%, Ti 0.01～0.15%, Al 0.02～0.05%, all the other are Fe and impurity.

2. steel for large diameter non-tempering petroleum sleeve as claimed in claim 1 is characterized in that: P in the described impurity≤0.025%, S≤0.020%.

3. steel for large diameter non-tempering petroleum sleeve as claimed in claim 1 is characterized in that: the carbon equivalent Ceq. of this steel is 0.66～0.75%, Ceq.=C+Mn/6+V/5.