US3769003A

US3769003A - Alloy steel particularly adaptable for use as a filler metal

Info

Publication number: US3769003A
Application number: US00131510A
Authority: US
Inventors: N Kenyon
Original assignee: International Nickel Co Inc
Current assignee: Huntington Alloys Corp
Priority date: 1971-04-05
Filing date: 1971-04-05
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30
Also published as: CA967407A

Abstract

An alloy particularly adaptable for use as a welding filler wire contains from 4 percent to 8 percent nickel, about 5 percent to about 11.5 percent chromium, about 1 percent to about 3.75 percent molybdenum, up to about 0.5 percent aluminum, up to about 0.3 percent titanium, up to about 0.03 percent carbon and the balance essentially iron. The alloys are also useful for structural and other applications.

Description

firmed e tates Patent [1 1 Kenyon Oct. 30, 1973 {5-4} ALLQY STEEL PARTICULARLY' 2,185,996 1/1940 Hatfield 75/128 W ADAPTABLE FOR USE s A FILLER 3,278,298 10/1966 Perry 75/128 W METAL 3,556,776 1/1971 Clarke 75/128 W 3,594,158 7/1971 Sadowski 75/128 W Norman Kenyon, Sloatsburg, N.Y.

The International Nickel Company, Inc., New York, N.Y.

Filed: Apr. 5, 1971 Appl. No.: 131,510

Inventor:

Assignee:

U.S. Cl. 75/128 W, 75/124, 75/128 T Int. Cl. C22c 39/20 Field of Search 75/128 W References Cited UNITED STATES PATENTS 9/1936 McIntosh 75/128 W Primary ExaminerHyland Bizot AttorneyMaurice L. Pinel [57] ABSTRACT 5 Claims, No Drawings ALLOY STEEL PARTICULARLY ADAPTABLE FOR USE AS A FILLER METAL 11 percent nickel, 8.75 percent to 11.5 percent chro-' mium, 1.4 percent to 3.75 percent molybdenum, at least one metal from the group consisting of aluminum and titanium in a total amount of 0.1 percent'to 0.65 percent, the aluminum not exceeding 0.4 percent and the titanium not exceeding 0.3 percent, carbon up to 0.04 percent, pp to 0.5 percent each of silicon and manganese, with the balance being essentially iron.

However, as is not uncommon with the development of new alloys various difficulties oftenarise and the above-described steels proved not to be an exception. For a rather frustrating problem evo'lved-in using matching filler metal compositions the steels could be welded over a fairly wide range of section sizes, e.g., from sheet to at least 1 inch thick plate, by the gas tung- In carrying the invention into practice, while the upper chromium percentage might be extended up to l 1.5 percent it is much preferred that it not exceed l l percent in order to avoid retained austenite. On the sten-arc (TIG) process, but in using the much faster,

less expensive conventional gas metal-arc (MIG) procedure, weld cracking manifested itself in respect of the thicker plate sections, i.e., above l/2 inch, and a substantial amount of impact toughness was lost even with sections on the order of 1/2 inch.

Now, as is well recognized, the weldability of an alloy is of vital importance to its commercial success in innumerable and diverse areas of application. This being the case, it became a prime objective-to find a solution to the MIG problem in order to take advantage of the economics offered by this technique and to remove an otherwise expected deterrent to the full commercial exploitation of the 10-1'0-2 steels, steels which had already demonstrated many attractive qualities. Of course, this required a filler material which would not only provide weld deposits free of deleterious cracks but which were also characterized'by mechanical properties approximating those of the l0-10-2 base'material welded. It would be no solution to achieve crack-free deposits at the expense of other indispensible metallurgical properties.

It has now been discovered that the above described problem is greatly minimized if not entirely obviated with novel filler metals containing correlated amounts of nickel, chromium, molybdenum, aluminum, titanium, etc., as herein described. Moreover, it has been further found that such filler metals are suitable for use in the welding of steels which differ compositionally from the 10-10-2 steels and this lends to their commercial significance.

Generally speaking, the present invention contemplates filler metals formed from alloys containing (in weight percent) from about 4 percent to less than 8 percent, e.g., 7.85 percent, nickel, about 8.5 percent to 11 percent chromium, about 1 percent to about 3.5 percent or 3.75 percent molybdenum, up' to about 0.5 percent aluminum, up to about 0.3 percent titanium, up to about 0.03 percent carbon, and the balance essentially iron.

other hand, while the chromium level might be extended down to as low as 5 percent or 6 percent where the intended use will not suffer for want of corrosion resistance, where the latter is of importance the tiller metal should contain at least 8 percent chromium.

The nickel content should be less than 8 percent to again minimize retained austenite. Furthermore, it has been determined that deposits of excellent toughness are obtained despite what might otherwise be considered as a low nickel plateau. This obtains down to as low as 6 percent nickel without significant loss in strength or corrosion resistance being encountered. At nickel levels of 4 percent, strength is lowered but such filler metals are deemed useful in welding alloys other than those of 10-10-2 type.

With regard to the constituents molybdenum, aluminum and titanium, these elements do not seemingly play a role significantly different from their respective roles in the l0-l0-2 steel. Molybdenum contributes to corrosion resistance and strength and the aluminum and titanium confer age hardening and strength.

A most advantageous filler metal in accordance herewith consists essentially of from about 6 percent to 7.8 percent nickel, about 9 percent to 10.5 percent chr0- mium, about 1.25 percent to 2.75 percent or 3 percent molybdenum, about 0.05 percent to 0.4 percent aluminum and/or about 0.05 percent to about 0.3 percent titanium, up to 0.03 percent carbon and the balance essentially iron. Another most preferred composition contains about 6 percent to 7.5 percent nickel, about 9.5 percent to 10.5 percent chromium, about 1.5 percent to about 2 percent molybdenum, about 0.1 percent or 0.2 percent to 0.4 percent aluminum, about 0.1 percent or 0.2 percent to'0.3 percent titanium, up to about 0.1 percent each of silicon and manganese, up to about 0.03 percent carbon and the balance essentially iron.

' For the purpose of giving those skilled in the art a better appreciation of the invention the following illustrative data are given.

Several 30-pound heats were vacuum melted, cast, worked and drawn down into filler metal welding wires 0.062 inch in diameter, the filler metals having compositions as given in Table I. Included in Table I is the composition of the 10-10-2 base plate (B.P.) welded. Filler metal A is without the invention whereas the others are within the scope'thereof.

Each of the wires was used to form a gas metal-arc weld (MIG) between two 1 inch thick sections of the base plate. The base plate had been aged for 3 hours at 900 F. and was in the restrained condition, i.e., heavy U-straps were used to restrain the welded joint to a 2- inch thick steel platen. The joint design was a single U- groove with a 15 side angle, a 1/4 inch root radius, and a 3/32 inch root face. The joints were filled in 10 passes, the welds being made at 30 volts, 300 amperes, and a 12 inch per minute travel speed while feeding 200 inches per minute of filler wire. Argon, flowing at about 50 cubic feet per hour, was used as the shielding gas and no preheat was utilized. The interpass temperature was maintained at or below about 200 F.

TABLEv 1 Percent Filler Ni Cr Mo Al Ti C Mn Si Fe A 9.8 9.3 1.95 .25 .16 .003 .14 .09 Bal. 1 7.8 9.5 1.99 21 .19 .004 .14 .07 Hal. 2 5.9 9.5 1.98 17 .17 .002 .13 .08 B211. 3 6.1. 9.5 1.91 .28 .18 .001 .081 .11 Bal. 4 4.3 8.9 1.95 .16 .24 .011 .075 .096 Bal. 13.1. 10.0 10.5 2.1 .40 .23 .032 .1 1 .09 3211.

The weld deposits were radiographically examined, Charpy V-notch samples machined from the bars and polished and etched transverse slices taken from yielded the following results: the deposits were microscopically examined at 30x TABLE I magnification. Standard transverse tensile and Charpy 15 V-notch specimens were machined from the welds and CVN o Filler Y.S. U.T.S. El. R.A. RT then aged at 900 F. for 3 hours before test. These re l 163g [To 715 140 M4 sults (average) are reported in Table 11. 2 141.6 147.5 19.0 74.0 175,150

TABLE 11 El. R.A. Weld Microscopic Y.S. U.T.S. (per- (per- CVN deposit X-ray at30x (1 .s.i.) (k.s.i.) cent) cent) (ft. lbs.)

A sound cracks 166.4 170.1 8 33 22 1 ...do..... nocracks 173.7 175.3 13 60.5 48 2 160.5 161 14 67 87 3 161.4 163 13 60.5 77 4 129.1 135.7 15 72.5 150 It will be observed from the foregoing data that although each of the five weld deposits was seemingly 30 crack-free upon radiographic examination, cracks were detected during microscopic examination of the deposit formed using Filler Metal A. Despite the fact that Filler Metals l and 2 were of considerably lower nickel content than the matching Filler Metal A, no appreciable loss in toughness or strength was experienced; in fact, an increase of toughness was obtained.

It should be pointed out, that the strength level of the deposit obtained using Filler Metal 4 was relatively low; however, the toughness of this deposit was extremely high. These data indicate that such filler metals are useful in welding other materials. In this connection it is considered that steels, particularly cast steels, of the following composition would be amenable to welding with such welding wires: percent to l 1 percent nickel, percent to percent chromium, the sum of the nickel plus chromium being from 18 percent to 22 percent, about 0.5 percent to 3 percent silicon, titanium and/or aluminum up to 0.2 percent each, up to 1 percent manganese, up to 0.5 percent carbon and the balance essentially iron.

While the subject invention as above described has been set forth solely in connection with filler welding wires, the alloy compositions contemplated herein are also suitable for use in sundry other areas where steels capable of affording a good combination of strength, toughness, corrosion-resistance, workability, fabricability, etc., would find utility. Specifically, such compositions are considered useful in the production of steel castings for such potential applications as pumps and impellers and as structural members for applications particularly requiring corrosion resistance and high toughness. As illustrative of the latter utility, the Fillers l and 2 of Table l were also produced as l/2 inch hot rolled bars which were then annealed at l,500 F. for 1 hour and aged at 900 F. for 3 hours. Tensile and Pressure vessels and sheet for architectural purposes are also contemplated for use in accordance herewith.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

1 claim:

1. An alloy adaptable for use as a welding filler material and consisting essentially of from 4 percent to 7.85 nickel, about 8.5 percent to about 11 percent chromium, about 1 percent to about 3.75 percent molybdenum, up to about 0.5 percent aluminum, up to about 0.3 percent titanium, up to about 0.03 percent carbon and the balance essentially iron.

2. An alloy in accordance with claim 1 containing at least 6 percent nickel, at least 8 percent chromium, about 1.25 percent to 2.75 percent molybdenum, about 0.05 percent to 0.4 percent aluminum and/or about 0.05 percent to 0.3 percent titanium.

3. An alloy in accordance with claim 1 in which the aluminum is from 0.2 percent to 0.4 percent and the titanium is from 0.2 percent to 0.3 percent.

4. A filler metal welding wire formed from the alloy set forth in claim 1.

5. A filler metal welding wire formed from the alloy set forth in claim 2.

Claims

2. An alloy in accordance with claim 1 containing at least 6 percent nickel, at least 8 percent chromium, about 1.25 percent to 2.75 percent molybdenum, about 0.05 percent to 0.4 percent aluminum and/or about 0.05 percent to 0.3 percent titanium.
3. An alloy in accordance with claim 1 in which the aluminum is from 0.2 percent to 0.4 percent and the titanium is from 0.2 percent to 0.3 percent.
4. A filler metal welding wire formed from the alloy set forth in claim 1.
5. A filler metal welding wire formed from the alloy set forth in claim 2.