JPH02147195A - Production of cobalt-chromium-based alloy welding material - Google Patents

Abstract

PURPOSE:To allow the production of the welding rod consisting of a cobalt- chromium-based alloy by forging, rolling and drawing and to improve the yield thereof by suppressing the content of C in the alloy at specific % in the stage of smelting of a cast ingot, working the alloy to a rod or wire and then increasing the content of the C up to specific % after the working. CONSTITUTION:This welding material contains, by weight %, 20.0 to 40.3% Cr and further, any one or >=2 kinds of 0.10 to 20% W, 0.10 to 10% Mo, 0.10 to 40% Ni, and 0.10 to 5% Fe are incorporated therein. The content of the C in the cobalt-chromium-based alloy which consists of the balance Co aside from C and unavoidable impurities is specified to 0.0001 to 0.10% and the casting ingot of this alloy is smelted. The ingot is subjected to hot rolling to a wire rod after hot forging and is further subjected to warm or cold drawing to form the wire. The large-diameter wire is subjected to a carburization treatment after working to a straight rod and the fine wire is subjected to the above- mentioned treatment as it is to form the wire to increase the content of C of the alloy to 0.10 to 3.50%. The welding rod and welding wire made of the cobalt-chromium-based alloy are thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a welding rod and welding wire for hard overlay made of a cobalt-chromium based alloy.

[Conventional technology]

Conventionally, cobalt-chromium-based alloys, typically stellite alloys, have high wear resistance and high temperature hardness, and have thermal expansion coefficients and melting temperatures close to those of steel, so they have been prized as alloys for hardfacing. In particular, it is harder than high speed steel at temperatures above 600°C.

For this reason, it is widely used in the molding of exhaust valves in automobiles and aircraft engines, as well as in the silk industry and plastic molding equipment due to its abrasion resistance.

[Problem that the invention seeks to solve]

Conventionally, welding rods made of stellite alloy have been manufactured by centrifugal casting or vacuum suction, but due to limitations in the processing method, the length is at most 40 to 200 mm.
I could only get a small stick.

Moreover, the yield was extremely low.

Therefore, the present invention does not rely on the above-mentioned special casting method, but instead uses forging,
The object of the present invention is to provide a method for manufacturing cobalt-chromium-based alloy welding rods and welding wires, such as stellite alloys, by rolling.

[Means for solving problems]

The present invention has Cr:20.0 as a main component at a weight ratio of 1.
~40.0%, or additionally W:0.
10-20%, Mo: 0.10-10%, Ni:
The C content in a cobalt-chromium-based alloy containing one or more of the following: 0° 10-40% and Fe: 0.10-5%, with the remainder being Co, excluding C and inevitable impurities. An ingot with a concentration of 0.0001 to 0.10% is produced, hot forged, hot wire rolled, and then warm or cold wire drawn to form wires of φ1 to φ5. However, after processing the thick wire into a straight bar, the thin wire is carburized as it is to make the C content of the alloy 0.10 to 3.50%.
The company manufactures cobalt-chromium-based alloy welding rods and welding wire.

Such the present invention provides a cobalt-chromium based alloy welding rod,
This was discovered by the present inventor in the process of investigating various means to enable wire to be formed from an ingot by forging and rolling, and the C content in the alloy was reduced to 0. 00
By keeping the C content as low as 0.01 to 0.10%, it is possible to forge and roll it, and after processing it into bars and wires, it is carburized to reduce the C content to 0. , 10 to 3.50%.

Note that the cobalt-chromium-based alloy according to the present invention contains up to 2.0% S as an unavoidable impurity as a desulfurization agent.
i, AD up to 0.5%, , Ti, etc., and [1
The inclusion of up to 2.0% Mn as an agent is acceptable.

C: 0.0001 to 0.10% C is limited to 0.10% or less because if it is contained in an amount of 0.10% or more during melting, cracks will occur in the subsequent casting process.

C content after carburizing: o4o ~ 3.50% If C is less than 0.10%, high-temperature hardness and wear resistance of the weld build-up part cannot be obtained. On the other hand, if it is 3.50% or more, the cracking resistance of the weld build-up part decreases, so it is set to 3.50% or less.

Examples are shown below.

EXAMPLES Alloys having chemical compositions of samples Nα1 to Nα16 as shown in Table 1 were melted and the resulting ingots were subjected to forging tests. The forging test conditions were as follows.

Ingot size 50kg (D: 120mm, L: 6
00mm) Forging diameter size: 50φX3m Temperature: 1200°C (blank below) The results of this forging test are shown in Table 1 along with the chemical components. From Table 1, it can be seen that when the C content in the cobalt-chromium base metal ingot to be melted exceeds 0.10%, cracks occur in the ingot and it is impossible to forge. This shows that it cannot withstand the subsequent hot wire rod rolling process. On the other hand, it can be seen that when the C content in the ingot is 0.10% or less, no cracks occur during forging. Further, even in subsequent hot wire rolling and warm or cold wire drawing, rolling and wire drawing were possible without cracking.

Next, samples Nα2, 4, 6, 8, and 12.14 were forged and then hot-rolled to φ10 at 1200°C.
Further, wires having diameters of φ1 to φ4 were produced by cold wire drawing. φ
4. A relatively thick wire with a diameter of 3.2 mm was processed into a straight rod and then carburized to make a welding rod.

Also, relatively thin wires of φ1.2 are carburized as they are,
The weld wire was carburized to a C content as shown in Table 2. Samples Nαl and 3.5°7.9.13 were made into welding rods by conventional centrifugal casting. As a result of overlay welding using the above welding material, there were no problems and the welding material could be stably supplied. By the way, when we determined the hardness (HRC) of the weld metal layer of the overlay weld, as shown in Table 2, the hardness of the weld metal using the welding rod or welding wire produced according to the present invention was that of centrifugal casting. It showed almost the same hardness as that obtained in . This shows that the welding rod or welding wire produced by the present invention is not significantly different in performance from the welding rod produced by the conventional method.

(Left below) Furthermore, the welding rod or welding wire produced by the present invention can be of any length, and the length of the welding rod obtained by conventional centrifugal casting is about 40 to 200 an. The number of times the welding rod needs to be replaced can be significantly reduced, and work efficiency is greatly improved.

〔Effect of the invention〕

According to the present invention as described above, welding rods and welding wires made of a cobalt-chromium based alloy for hard overlay can be forged,
Because it is obtained by rolling and wire drawing, the manufacturing yield is extremely high.
The manufacturing cost is significantly reduced, the number of replacement operations for welding rods or welding wires of arbitrary length can be reduced or omitted, and work efficiency is significantly improved.

Patent applicant: Daido Steel Co., Ltd.

Claims (1)

[Claims] 1. Contains Cr: 20.0 to 40.0% by weight,
An ingot is produced with a C content of 0.0001 to 0.10% in an alloy in which the balance consists of Co, excluding C and unavoidable impurities, which is then rolled, further wire-drawn, and then made into a straight bar. A method for producing a cobalt-chromium-based alloy welding material, which comprises carburizing the alloy to have a C content of 0.10 to 3.50% after processing or as it is. 2. The alloy in the method according to claim 1 further contains W: 0.10-20%, Mo: 0.10-10%,
A method for producing a cobalt-chromium-based alloy welding material containing one or more of Ni: 0.10 to 40% and Fe: 0.10 to 5%.