JPS6033180B2 - High hardness shank material for high speed steel tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-hardness shank material that is used by joining high-speed steel as a blade by various welding methods.

Materials conventionally used as shank materials for high-speed steel tools include S5& and Yama SI6150, but these have the disadvantage of being inferior in strength, rutting resistance, weldability, etc.

Furthermore, although various improvements have been made to shank materials, conventional shank materials still do not have sufficient hardness and lack strength when heat treated simultaneously with high-speed steel when used in applications that are subject to strong compressive stress, such as punching tools. This causes accidents such as buckling, making it unusable. In addition, there are materials such as SKD61 that achieve the purpose in terms of strength, but they contain a large amount of alloy and are expensive, so they cannot be used as a shank material.
In order to solve these drawbacks, the present invention has developed a material that is much cheaper than SKD61, etc., and can be used under high stress conditions, stably achieving high hardness of at least HRC55 even when treated simultaneously with high-speed steel. It is intended to be a suitable shank material, CO. 5-0.75%, Sil. 1-1.5
%Mnl. 0% or less, Cr4.1-5.0%, Moo.
35-0.75%, VO. 50 to 1.5%, and depending on the blade material, bending stress is applied in addition to compressive strength, and when toughness is required, N and N may be added depending on the usage conditions.
bo. 01 to 0.3%, one or two types, Nio.
This was achieved by a component composition containing 2 to 1.5% of Fe, with the balance consisting of Fe and impurities.

The reasons for limiting the ingredients of the present invention will be described below.

C is an essential element that dissolves in the matrix and strengthens it, and it is necessary to contain 0.50% or more, but if it exceeds 0.75%, the toughness will decrease significantly due to high temperature aging, so the component range was set at 0.50 to 0.75%. Si is used as a deoxidizing agent and is an effective element for increasing resistance to reversal softening and strength, but if it is less than 1.1%, the effect decreases, making it necessary to increase the amount of expensive Mo or V added. . In order to make the shank material as inexpensive as possible, the lower limit is set to 1.
．． It was set at 1%. However, if it exceeds 1.5%, the toughness and workability deteriorate, so it is set at 1.5% or less. Mn is used as a deoxidizing agent, and the amount added is usually 1.0% or less, so the component range is 1.0% or less. Cr forms a carbide, and a part of it is solidly dissolved in the matrix to improve hardenability, and at the same time prevent coarsening of crystal grains due to high-temperature quenching, thereby preventing deterioration in toughness.

In addition to increasing the resistance to tempering and softening, Cr also has the effect of adjusting the activity of C and reducing the diffusion of C, such as decarburization and carburization, with high-speed steel. In order to effectively exhibit the above effects, it is desirable that the Cr content be 4.1% or more, but even if it exceeds 5.0%, no effect commensurate with the content will be observed, and the toughness will decrease in relation to the C content. Therefore, the range of Cr content was set to 4.1 to 5.0%. Mo is an element that is effective in improving hardenability and secondary hardening, and the higher the content, the more effective it is, but on the other hand, it is an expensive element.

The present invention achieves the following by taking appropriate mixing relationships with other elements.
A content of 0.35 to 0.75% shows sufficient effects, and stable hardness can be obtained by simultaneous heat treatment with high speed steel. V
Like Mo, is an element that imparts secondary hardenability and at the same time prevents coarsening of crystal grains during quenching and improves ballability.

In the steel of the present invention, the V content is set to 0.50% or more in order to provide sufficient secondary hardenability and high hardness due to high temperature resetting similar to high speed steel. However, if the amount of V exceeds 1.5%, a decrease in hardness or embrittlement occurs due to the formation of carbides due to the relationship with the amount of C, so the range of the V content is set to 0.50 to 1.5%. Ni has the effect of improving competitiveness and imparting toughness, but for this purpose it is necessary to have a content of 0.2% or more, and if it is contained in excess, the hardness decreases, so it is 1.5% or less. limited to.

AI is an element that is effective in preventing bubbles in the weld zone during various types of welding, and at the same time has the effect of preventing coarsening of crystal grains during dawn penetration.

For these effects, a content of 0.01% or more is required, but if it exceeds 0.3%, non-metallic inclusions will increase, which is harmful to toughness, so the content of mountains should be 0.01~ 0.3%
And so. Nb is a carbide-forming element with a high melting point, and has the effect of preventing coarsening of crystal grains when heated to high temperatures.

This tendency is observed from 0.01%, but there is no significant increase in the effect when the content exceeds 0.3%, and on the other hand, workability deteriorates, so the upper limit was set at 0.3%. Next, the present invention will be explained by examples.

Table 1 shows Examples A to 1 of the steel of the present invention, conventional steel J, and comparative steel K.
, L, M, and N.

Table 1 Table 2 Table 2 shows a comparison of the heat treatment conditions and hardness and mechanical properties of these steels.

The inventive steel has much greater strength than the comparison steel.

Claims (1)

[Claims] 1% by weight: C0.50-0.75%, Si1.1-1
．． 5%, Mn 1.0% or less, Cr 4.1-5.0%, M
o0.35-0.75%, V0.50-1.5% balance F
A high-hardness shank material for high-speed steel tools consisting of E and some impurities. 2 C0.50-0.75% by weight, Si1.1-1
．． 5%, Mn 1.0% or less, Cr 4.1-5.0%, M
Contains one or two of o0.35-0.75%, V0.50-1.5%, Al0.01-0.3%, and Nb0.01-0.3%, the balance being iron and some impurities. High hardness shank material for high speed steel tools. 3 C0.50-0.75% by weight, Si1.1-1
．． 5%, Mn 1.0% or less, Cr 4.1-5.0%, M
o0.35-0.75%, V0.50-1.5%, Ni
A high hardness shank material for high speed steel tools consisting of 0.2 to 1.9 balance iron and some impurities. 4 C0.50-0.75% by weight, Si1.1-1
．． 5%, Mu1.0% or less, Cr4.1-5.0%, M
o0.35-0.75%, V0.50-1.5%, Ni
0.2-1.5% and Al0.01-0.3%, Nb
A high-hardness shank material for high-speed steel tools containing one or two of 0.01 to 0.3, with the balance being iron and some impurities.