US3472651A - Engine components of cast iron having ni,cr,and ti as alloying elements - Google Patents

Description

United States Patent 3,472,651 ENGINE COMPONENTS OF CAST IRON HAVING Ni, Cr, AND Ti AS ALLOYING ELEMENTS Kenneth E. Kueny, Muskegon, Mich., assiguor to Johnson Products, Inc., Muskegon, Mich., a corporation of Michigan N 0 Drawing. Continuation-impart of application Ser. No. 547,722, May 5, 1966. This application Sept. 22, 1966, Ser. No. 581,158

Int. Cl. C22c 39/54, 39/20, 39/00 US. Cl. 75-128 7 Claims ABSTRACT OF THE DISCLOSURE An internal combustion engine valve train component having at least a bearing surface of a hardenable ferrous alloy especially characterized by the presence of titanium carbide and titanium nitride compounds, the alloy consisting essentially of the following:

Element: Percent by weight Carbon 3.00-3.60 Silicon 2.00-3.00 Manganese 0.70-1.25 Nickel 0.15-0.70 Chromium 0.40-1.50 Molybdenum 0.15-0.70 Titanium 0.10-1.00 Iron (plus minor sulfur and phosphorus impurities) Balance 7 Consequently, substantial improvement have been made in many engine components to meet the increasing demands made. In the area of valve train components, various coatings, surface treatments, and the like have been employed on the conventional hardenable iron members in efforts to extend useful life. While these frequently do help, it has been believed advantageous by the inventor and assignee herein to increase useful tappet and camshaft life many times, even in high compression, high speed engines, by devising new valve train components not made of conventional hardenable iron, but of a new material.

Hence, on this basis, extensive experimental and testing work was conducted by and under the supervision of the inventor herein in efforts to develop valve train components formed of a special material that would enable them to have required operational characteristics but also be capable of greatly increased wearability so as to extend the useful life several times normal.

It is therefore an object of this invention to provide valve train components of a material found to provide wearability at least 3 times and usually from 6 to 8 times greater than conventional, to therefor have a greatly extended useful life. The novel valve train components are particularly advantageous in high speed, high compression engines of recent years.

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These and other objects of this invention will become apparent upon studying the following specification.

Through experimentation and testing, novel components were developed which were found to have wearability qualities several times that of conventional. This experimentation and subsequent analysis have shown that the presence of titanium carbide and titanium nitride is the key factor to the greatly increased hardness and wearability of the components. These compounds form during the melting and casting process by reaction between the titanium and carbon components, and between the titanium component and nitrogen gas introduced by passing air or nitrogen gas to the molten metal or by introducing nitrogen in some other manner as by using nitrogen hearing chromium as the chromium component.

The novel material is basically formed of the following composition range:

Element: Percent by weight Carbon 3.00-3.60

Silicon 2.00-3.00 Manganese 0.60-1.25 Phosphorus (impurity 0.00-0.20 Sulfur (impurity 0.00-0.10 Nickel 0.150.70 Chromium 0.40-1.50 Molybdenum 0.15-0.70 Titanium 0.10-1.00 Iron Balance The phosphorus and sulfur element are normal impurities which are almost invariable present in these ferrous alloys. They are not required and should not exceed the maximum percentages indicated.

The controlled percentage of titanium is essential and crucial to this novel valve train component composition. It has been found that amounts of about 0.10% of titanium are important to obtain the greatly increased wearability, and that amounts greater than about 1.00% titanium, e.g. up to about 5% by weight, although usuable, really do not add significant wearability, but merely add expense.

Typical examples of the novel composition tested are the following:

EXAMPLE 1 Element: Percent by weight Carbon 3.35 Silicon 2.51

Manganese .82 Nickel .61 Chromium 1.08 Molybdenum .40 Titanium .23

Iron (and minor phosphorus and sulfur impurities) Balance The valve train components, when tested, showed a wearability increase of 6 times that of conventional hardenable iron components.

The components showed a wearability increase of 3 times that of conventional hardenable iron components.

3 EXAMPLE 3 Element: Percent by weight Carbon 3.33 Silicon 2.45 Manganese .91 Nickel .24 Chromium .63 Molybdenum .27 Titanium .22 Iron Balance These components showed a wearability increase of times that of conventional hardenable iron components.

Preferably, the complete tappet, complete camshaft, and complete rocker arm are formed of the material.

The components may be cast by casting techniques wherein the material is melted by any standard melting method, then poured into suitable molds, such as sand molds, carbon dioxide molds, shell molds, or permanent molds. It can even be chilled against a carbon plate or similar heat extracting medium. It may be hardened by normal heat treating techniques such as those conventionally used on hardenable iron for such components, a typical heat treatment including heating to 1,580 F. holding about thirty minutes, then quenching in oil.

It is conceivable that certain minor variations from the specific compositions noted may be made within the concept presented. The invention is intended to be limited only by the scope of the appended claims and the reasonable equivalents thereto.

I claim:

1. An internal combustion engine valve train component comprising a body having at least a bearing surface of a hardenable ferrous alloy especially characterized by the presence of titanium nitride and titanium carbide and consisting essentially of the following composition:

Iron (plus minor sulfur and phosphorus impurities) Balance 2. The valve train component in claim 1 wherein said entire body is of said ferrous alloy.

3. The structure in claim 1 wherein said component is a tappet.

4. The structure in claim 1 wherein said component is a camshaft.

5. The valve train component in claim 1 substantially of the following composition:

Element: Percent by weight Carbon 3.33 Silicon 2.45 Manganese .91 Nickel .24 Chromium .63 Molybdenum .27 Titanium .22 Iron (plus minor sulfur and phosphorus impurities) Balance 6. The valve train component in claim 1 susbstantially of the following composition:

Element: Percent by weight Car-bon 3.57 Manganese .94 Silicon 2.64 Molybdenum .31 Chromium .68 Nickel .24 Titanium .15 Iron (and minor amounts of phosphorus and sulfur impurities) Balance 7. The structure in claim 1 wherein said component is a rocker arm.

References Cited