US3243286A - Hard surfacing alloy - Google Patents

Description

United States Patent Ill., a corporation of Illinois No Drawing. Filed July 26, 1962, Ser. No. 212,717 3 Claims. (Cl. 75-123) The present invention relates to hard surfacing alloys of the cast iron type for providing hard facing on metals by welding techniques.

Previously proposed hard facing compositions of the cast iron type were frequently satisfactory from the standpoint of hardness, tensile strength, and yield strength, but they frequently lacked adequate resistance to abrasion and, in some instances, suffered excessive reduction in their strength properties upon being heated to elevated temperatures.

The present invention provides an'improved hard surfacing alloy composition which can be used in the form of a welding electrode or welding rod and which overcomes the deficiencies of hard surfacing compositions heretofore produced. The compositions of the present invention, when applied as hard facings, exhibit excellent hardness properties, and resistance to abrasion. They are also capable of retaining, to a substantial degree, their improved physical properties at intermediately high operating temperatures.

The alloy compositions of the present invention are cast irons which contain nickel, molybdenum, tungsten, silicon, and manganese in controlled amounts to provide the desirable strength and hardness properties while in addition providing excellent resistance to abrasive wear.

An object of the present invention is to provide an improved hard facing material for application by electrical or gas welding.

A further object of the invention is to provide a hard facing alloy which When applied to a metal substrate exhibits excellent hardness and resistance to abrasion.

A further object of the invention is to provide an improved hard facing alloy which retains its improved physical properties even at intermediately high operating temperatures.

The improved hard facing material of the present invention has an analysis within the following ranges:

Percent Silicon 1.50 to 2.50 Manganese 0.50 to 1.00 Total carbon 2.50 to 3.50 Phosphorus 0.055 to 0.200 Sulfur 0.040 to 0.150 Nickel 2.00 to 4.00 Molybdenum 0.30 to 1.00 Tungsten 0.75 to 2.00

Iron, substantially the balance.

The improved physical properties of the alloys of the present invention are believed due, at least in part, to the proper correlation between the hardness imparting ingredients which include the nickel, molybdenum, tungsten, and manganese. For example, the particularly preferred a1- loys, according to the present invention, are those in which the nickel content ranges from about 2.0 to 4.0%, and in which the nickel to molybdenum ratio is about 4 to 3,243,286 Patented Mar. 29, 1966 to 1, the nickel to tungsten ratio is about 2 to 5 to l, and the nickel to manganese ratio is about 3 to 6 to l.

A particularly preferred alloy, coming within the scope of the present invention, has the following analysis:

Percent Silicon 2.07 Manganese 0.6 Total carbon 3.0 Phosphorus 0.075 Sulfur 0.05 Nickel 3.0 Molybdenum 0.5 Tungsten 1.5 Iron, substantially the balance.

The hard facing compositions of the present invention can be used either as welding rods in normal gas type welding, or as electrodes for electrical welding. For the latter use, it is desirable to employ the composition in the form of a rod having a mineral surface coating or the like.

In the as cast condition, the hard facing materials of the present invention evidenced areas of acicular graphite formation and some areas of cementite. When applied as a hard facing to a substrate, the deposit is characterized by the presence of martensite, austenite, and cementite, each of the constituents comprising roughly 10 to 50% of the total.

Tests made on the improved facing alloys of the present invention indicate that they are at least equivalent in physical properties to other hard facing compositions of the cast iron type, and have substantially improved abrasion resistance. For example, the tensile strength of the alloy is normally in the range from 40,000 p.s.i. to 55,000 pounds per square inch. The mechanical properties of a 1.2 inch diameter bar evidence transverse rupture stress in the range from about 3,000 to 5,000 pounds per square inch. The Brinell on a 1.2 inch diameter bar ranges from 250 to 300 B.H.N. hardness when applied as a facing ranges from about 350 to 600 since the material is work hardenable.

From the foregoing, it will be evident that the hard facing compositions of the present invention provide an improved material for application to surfaces which require a coating of a hard facing material for abrasion resistance. It will also be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.

I claim as my invention:

1. A cast iron Welding rod having improved resistance to abrasion and consisting essentially of the following:

Iron, substantially the balance.

2. A cast iron welding rod having improved resistance to abrasion 'and consisting essentially of the following:

Iron, substantially the balance said rod in the as cast condition evidencing areas of acicular graphite formation and some areas of cementite. 3. A cast iron welding rod having improved resistance to abrasion and consisting essentially of the following:

Percent Silicon 1.50 to 2.50 Manganese 0.50 to 1.00 Total carbon 2.50 to 3.50 Phosphorus 0.055 to 0.200 Sulfur 0.040 to 0.150 Nickel 2.00 to 4.00 Molybdenum 0.30 to 1.00 Tungsten 0.75 to 2.00

Iron, substantially the balance said rod in the as cast condition evidencing areas of acicular graphite formation and some areas of cementite,

and when deposited as a facing, the facing being characterized by the presence of areas of martensite, austenite, and cementite.

References Cited by the Examiner UNITED STATES PATENTS 1,166,342 12/1915 Field et a1. 75123 1,803,634 5/1931 Morgan 148--24 1,944,178 1/1934 Hornerberg 75124 X 1,999,888 4/1935 Ammann 75l23 X 2,145,757 1/1939 Ervin 75123 X 2,165,022 7/1939 Anderson 75--123 X 2,184,518 12/1939 Eash et al. 75-124 X 2,266,762 12/ 1941 Jerabek 75123 X 2,485,761 10/1949 Millis et a1. 75123 X 2,507,195 5/1950 Colbeck'et al 75-123 2,516,524 7/1950 Millis 75-123 2/1957 Borneman et a1. 75123 X OTHER REFERENCES I Li & Wang, Tungsten, Reinhold Publ. Corp., 2nd edition, 1947, pages 330, 333-334.

The Metals Handbook, article on page 722 (1948 edition).

DAVID L. RECK, Primary Examiner.

HYLAND BIZOT, Examiner.

N. F. MARKVA, P. WEINSTEIN, Assistant Examiners.

Claims (1)

1. A CAST IRON WELDING ROD HAVING IMPROVED RESISTANCE TO ABRASION AND CONSISTING ESSENTIALLY OF THE FOLLOWING: