JPS6211060B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an alloy for cast tools having high toughness, and more specifically, it improves toughness and durability by refining carbides in a cast state and making their distribution uniform. This invention relates to an alloy for casting tools that has high strength and good wear resistance. Conventionally, carbide bits have been used for difficult cutting applications that involve impact, such as groove cutting and hot deburring of super heat-resistant steels, austenitic stainless steels, and high-Mn steels.
Co-based high-speed tool steel lacks cutting durability, which causes fatigue, wear, etc. Stellite-based cast alloys are used for applications that require high strength and wear resistance at room and high temperatures. However, the main cause of chipping, fatigue, and wear that occurs in cutting tools is due to the carbide distribution inherent in the cutting tool material, which has the disadvantage that thick tools cannot be manufactured using stellite-based cast alloys. . In this case, an inexpensive base material is used and a stellite-based cast alloy is built up in the necessary parts, but the built-up base shows a cast structure, and giant carbides are long and continuous along the grain boundaries. The reality is that they grow in a net-like or dendrite-like shape, causing deterioration in toughness and causing various troubles when using tools. It is no exaggeration to say that the life of a cutting tool is determined by the quality of the distribution of carbides. Furthermore, in order to improve the toughness and wear resistance of cast alloys used as overlays in molds and other tools, it is essential to improve the distribution of carbides. The present invention refines the carbides in cast alloys used as materials for these tools and makes their distribution uniform. In order to solve this problem, the present inventors have discovered the following as a result of various studies. That is, by adding rare earth elements (REM), Y, Hf or Sc to conventional casting tool alloys,
In the temperature range of 1400 to 1500°C, carbides such as rare earth elements are formed directly in molten steel. This rare earth carbide is very fine and does not segregate in a part of the molten steel. These fine carbides become the core of the carbide reaction during solidification, and the ledebrite eutectic reaction is completed in a short time. For this reason, the eutectic carbide has a very uniform shape, and no giant carbide is formed. Therefore, when looking at the microstructure of the product, a structure in which fine carbides are uniformly distributed can be obtained. As described above, the present invention provides a highly tough material for tools that prevents the carbide from becoming large and segregation, and the gist of the present invention is to provide a material for tools that is highly tough and prevents carbides from becoming large and segregated.
One or more of REM, Y, Sc, Hf each
It is an alloy for casting tools, which is characterized by containing 0.001 to 0.6%. In addition, the alloy for casting tools referred to in this application has a basic chemical composition of % by weight,
C: 1.0~4.0%, Cr: 25.0~35.0%, W: 10.0~
25.0%, Co: 35.0 to 65.0%, balance Fe and unavoidable impurities, and various performance improving elements are added to this composition, and the present invention provides these alloys for casting tools, REM, Y,
It contains 0.001 to 0.6% of one or more selected from the group consisting of Sc and Hf.
Among the alloys of the present invention, the following alloys may be mentioned as alloys to which the above-mentioned performance improving elements are added. That is, in weight ratio, C: 1.0 to 4.0%, Cr:
25.0~35.0%, W: 10.0~25.0%, Co: 35.0~
65.0%, and 0.001 to 0.6% each of one or more types selected from the group consisting of REM, Y, Sc, and Hf.
and, if necessary, Si: 0.03~3.0%, and
One or two selected from the group consisting of Ni: 0.01-15.0%, Mn: 0.05-10%, and further Mo: 0.05
~15.0%, V: 0.1~15.0%, Nb: 0.1~15.0%,
Ta: 0.1~10.0%, Ti: 0.01~0.5%, Zr: 0.01~
0.5%, Al: 0.1~0.5%, N: 0.02~0.15%,
B: An alloy for casting tools containing one or more selected from the group consisting of 0.005 to 0.8%, and the balance being Fe and unavoidable impurities. Next, the reason for limiting the composition range of the alloy of the present invention will be described below. C: 1.0 to 4.0% C is dissolved in austenite to increase the hardness of the matrix, and also forms hard double carbides with Cr, W, Mo, V, etc., and provides the wear resistance necessary for tools at room and high temperatures. It has a significant effect on improvement. C
If it is less than 1.0%, the amount of the double carbide produced is small, the hardness is too low, and the required performance cannot be obtained. However, if C is contained in a large amount exceeding 4.0%, the toughness will decrease, so the content range is 1.0 to 4.0%.
And so. Cr: 25.0 to 35.0% Cr combines with C to form carbide, which greatly contributes to improving wear resistance and increasing strength. If Cr is less than 25.0%, the effect is small, and
If added in an excessive amount exceeding 35.0%, the double carbide becomes coarse and brittle, so the content was set at 25.0 to 35.0%. W: 10.0 to 25.0% W combines with C to form a hard carbide, which is effective in increasing hardness at room temperature and high temperature, improving wear resistance, and increasing cutting durability. However, if added in too large a quantity, the toughness will decrease and chipping or cracking will occur, so the content was set at 10.0 to 25.0%. Co: 35.0-65.0% Co makes the base austenitic structure, improves toughness and increases high-temperature strength, but if it is less than 35%, high-temperature strength is insufficient and cutting durability decreases.
It was set at 35.0% to 65.0%. REM, Y, Sc, Hf: 0.001 to 0.6% each REM (La, Ce, Pr, Nd, Sm, others), Y,
Sc and Hf have the effect of dispersing carbides extremely finely and uniformly, and are effective in improving toughness and wear resistance. However, if added in large amounts, the toughness will decrease, so each content was set in the range of 0.001 to 0.6%. Si: 0.03-3.0% Si is also added as a deoxidizing agent, but it also strengthens the solid base, increases the yield point, prevents surface oxidation at high temperatures, and improves the fatigue limit. Also, if added in a large amount, it is effective in making carbides finer. However, if added in a large amount, the tool life will be shortened due to a decrease in thermal conductivity and deterioration of toughness, so it was set in the range of 0.03 to 3.0%. Mn: 0.05-10%, Ni: 0.01-15.0% Both Mn and Ni are elements that strengthen the base and improve the wear resistance, heat resistance, and durability of the tool.
However, even if they are added in large amounts, these performance improvements cannot be expected much, so each component was kept within the above-mentioned range. V: 0.1~15.0%, Mo: 0.05~15.0%, Nb: 0.1~
15.0%, Ta: 0.1-10.0% V, Mo, Nb, Ta all form carbides,
It greatly contributes to improving wear resistance and increasing strength.
However, if too large a quantity is added, the double carbide becomes coarse and brittle, so each component was set in the above range. Ti: 0.01~0.5%, Zr: 0.01~0.5%, Al: 0.1~
0.5%, N: 0.02-0.15%, B: 0.005-0.8% Ti, Zr, Al, N, and B are all elements that contribute to improving toughness and strength.
N has the effect of making crystal grains finer. B also suppresses the precipitation of pro-eutectoid carbides at austenite grain boundaries during the quenching and cooling process. However, if added in large amounts, Ti, Zr, Al, and N will have a large amount of nonmetallic inclusions, and B will form a large amount of boride and become brittle, so each of them was set within the above range. Next, the features of the present invention will be explained using examples. Examples Table 1 shows the chemical compositions of test materials of the invention alloy and comparative alloy.

【table】

[Table] Alloys with the 12 chemical compositions shown in Table 1 were cast into graphite molds to create bending test samples of 5 mm x 80 mm and casting tools of 10 mm x 80 mm. Table 2 compares the toughness of each sample by performing static bending tests on as-cast samples, and it can be seen that the alloy of the present invention has higher toughness than the comparative alloy.

【table】

[Table] Table 3 shows the results of cutting performance tests conducted on cast bits of each sample number. In addition, in the cutting performance test, H _B 145 was used as the work material.
SUS27 steel (70 mm) was cut at a cutting speed of 60 m/min, depth of cut of 1 mm, and feed of 1.08 mm, and the cutting durability time at this time was determined. Furthermore, the cutting tool used for cutting is in an as-cast condition. The results show that the alloy of the present invention has excellent machinability. Although the cutting tool used in this example is as-cast, it may be heat-treated in order to further improve durability.

【table】

[Table] As explained above, the alloy for cast tools of the present invention has extremely fine carbides by adding REM, Y, Sc, or Hf, and has the toughness, wear resistance, cutting durability, etc. required for tools. It exhibits excellent performance not only as casting tools such as cutting tools, molds, and punches, but also as welding overlays.

Claims (1)

[Claims] 1% by weight: C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0 to 25.0%, Co: 35.0 to 65.0%, and 1 selected from the group consisting of REM, Y, Sc, and Hf.
Contains 0.001 to 0.6% of each species or two or more species, the remainder
An alloy for casting tools consisting of Fe and unavoidable impurities. 2 In weight%, C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0-25.0%, Co: 35.0-65.0%, Si:
0.03 to 3.0%, and 0.001% each of one or more selected from the group consisting of REM, Y, Sc, and Hf.
An alloy for casting tools containing ~0.6%, with the balance consisting of Fe and unavoidable impurities. 3 In weight%, C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0 to 25.0%, Co: 35.0 to 65.0%, and one or two selected from the group consisting of Ni: 0.01 to 15.0%, Mn: 0.05 to 10%, and further
Contains 0.001 to 0.6% of one or more selected from the group consisting of REM, Y, Sc, and Hf, with the balance being Fe.
Alloys for casting tools consisting of and unavoidable impurities. 4 In weight%, C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0-25.0%, Co: 35.0-65.0%, and Mo: 0.05-15.0%, V: 0.1-15.0%, Nb: 0.1
~15.0%, Ta: 0.1~10.0%, Ti: 0.01~0.5%,
Zr: 0.01~0.5%, Al: 0.1~0.5%, N: 0.02~
0.15%, B: contains one or more selected from the group consisting of 0.005 to 0.8%, and further contains REM,
An alloy for casting tools containing 0.001 to 0.6% of one or more selected from the group consisting of Y, Sc, and Hf, with the balance being Fe and inevitable impurities. 5 In weight%, C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0-25.0%, Co: 35.0-65.0%, Si:
0.03~3.0%, and Ni: 0.01~15.0%, Mn:
1 or 2 selected from the group consisting of 0.05-10%
0.001 to 100% each of one or more species selected from the group consisting of REM, Y, Sc, and Hf.
An alloy for casting tools that contains 0.6% and the balance is Fe and unavoidable impurities. 6 Weight%: C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0-25.0%, Co: 35.0-65.0%, Si:
0.03~3.0%, Mo: 0.05~15.0%, V: 0.1
~15.0%, Nb: 0.1~15.0%, Ta: 0.1~10.0%,
Ti: 0.01~0.5%, Zr: 0.01~0.5%, Al: 0.1~
0.5%, N: 0.02~0.15%, B: 0.005~0.8%, including one or more types selected from the group consisting of
Furthermore, it contains 0.001 to 0.6% each of one or more types selected from the group consisting of REM, Y, Sc, and Hf,
Alloy for casting tools consisting of balance Fe and unavoidable impurities. 7 In weight%, C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0 to 25.0%, Co: 35.0 to 65.0%, and one or two selected from the group consisting of Ni: 0.01 to 15.0%, Mn: 0.05 to 10%, and further
Mo: 0.05~15.0%, V: 0.1~15.0%, Nb: 0.1~
15.0%, Ta: 0.1~10.0%, Ti: 0.01~0.5%,
Zr: 0.01~0.5%, Al: 0.1~0.5%, N: 0.02~
0.15%, B: contains one or more selected from the group consisting of 0.005 to 0.8%, and further contains REM,
An alloy for casting tools containing 0.001 to 0.6% of one or more selected from the group consisting of Y, Sc, and Hf, with the balance being Fe and inevitable impurities. 8 Weight%: C: 1.0-4.0%, Cr: 25.0-35.0
%, W: 10.0-25.0%, Co: 35.0-65.0%, Si:
0.03~3.0%, and Ni: 0.01~15.0%, Mn:
1 or 2 selected from the group consisting of 0.05-10%
Including seeds, Mo: 0.05-15.0%, V: 0.1-
15.0%, Nb: 0.1~15.0%, Ta: 0.1~10.0%,
Ti: 0.01~0.5%, Zr: 0.01~0.5%, Al: 0.1~
0.5%, N: 0.02~0.15%, B: 0.005~0.8%, including one or more types selected from the group consisting of
Furthermore, it contains 0.001 to 0.6% each of one or more types selected from the group consisting of REM, Y, Sc, and Hf,
Alloy for casting tools consisting of balance Fe and unavoidable impurities.