JPS583943A - Alloy for tool - Google Patents

Abstract

PURPOSE:To obtain an alloy for a tool with high strength at ordinary temp. and high temp. and satisfactory wear resistance by adding one or more among a very small amount each of a rare earth element, Y, Sc and Hf to an alloy for a casting tool to enhance the toughness and endurance. CONSTITUTION:One or more among 0.001-0.6% each of a rare earth element (REM), Y, Sc and Hf are added to an alloy for a casting tool having a composition consisting of about 1.0-4.0% C, about 25.0-35.0% Cr, about 10.0-25.0% W, about 35.0-65.0% Co and the balance Fe with inevitable impurities ro contg. further si, Ni, Mn, Mo, V, Nb, Ta, Ti, Zr, Al, N, B, etc. Thus, carbides of REM, etc. are directly formed from the molten steel. The carbides are very fine, do not cause segregation and make eutectic carbide fine and uniform, enhancing the characteristics as an alloy for a tool.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alloy for cast tools having high toughness.
The present invention also relates to an alloy for casting tools that improves toughness and durability by uniformly distributing the alloy, has high strength at room temperature and high temperature, and has good abrasion resistance.

Conventionally, super heat-resistant steel and austenitic stainless steel were made with high M
For difficult cutting applications where impact is applied, such as grooving and hot cutting of N steel, carbide bits may break due to lack of toughness, and high-CO high-speed tool steels may Due to the additional cutting durability of $2V, wear and tear will occur.

Stellite-based cast alloys are used in applications where wear resistance is required and the wear resistance is severe 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, so large tools cannot be manufactured using stellite-based cast alloys.

In this case, an inexpensive composite material is used to build up a stellite-based cast alloy layer in the necessary areas. However, the built-up base shows a cast structure, and the giant carbides are long and continuous along the grain boundaries. The reality is that the glaze grows in a net-like or dendrite-like pattern, deteriorating its toughness and causing problems with the glaze 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. It is also essential to improve the distribution of carbides in order to improve the toughness and wear resistance of glazing alloys that are used as overlays in small molds and other tools.

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 discovered the following as a result of research by Yuyu. That is, by adding rare earth elements (REM), Y, Hf or Sc to conventional cast tool alloys, it is possible to improve
In the temperature range of 0°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 product microstructure, a structure in which fine carbides are uniformly distributed is obtained.

As described above, the present invention provides a highly tough material for tools that prevents carbides from becoming large and segregation, and the gist thereof is to add REM, Y, Sc to alloys for cast tools.
, 10 or more than Vi2 M at 0.00 each
It is an alloy for casting tools characterized by containing 1 to 0.6%. The alloy for casting tools referred to in this application has a chemical composition of ci, o~4.0ft, Cr 25. [l
~35.0%, W I C1,Q~25. (J%,
C.

An alloy consisting of 35.0 to 65.0% balance Fe and unavoidable impurities, and various performance-improving elements added to this component composition, and the present invention applies REM, Y, It contains one or more of Sc and Hf in an amount of o, ooi to 0.6%, respectively. Among the alloys of the present invention, examples of alloys to which the above-mentioned performance-improving elements are added include the following &.

C1,0-4. Ofb, Cr 25.0-35.0%
, Wl 0.0~25.0%, Co 35.0~
65.0%, REM, Y, Sc, I (one or two types of f with 0.001 to 0.6- each on v, and SiO, 03 to 5.0% as necessary, NiO,01~1
5.0%.

One or two glazes containing Mn 0.05 to 10% and Mo0.
05-15.0%, Vo, 1-15.0'%, Nb
One or more of I'1.1 to 15.0%, Ta0, 1 to 10.0%, and TiO, [ ] 1 to 0.5%,
ZrO, 01-0.5%, AAo, 1-0.5%
, NO, 02 to 0.15%, Bo, 005 to 0.8% of 18f- or two or more thereof, and the balance is Fe and unavoidable impurities.

Next, the reason for limiting the composition range of the alloy of the present invention will be described below.

C: t [l ~ 4, O C is dissolved in austenite to increase the hardness of the matrix, and forms hard double carbides with Cr, W, MO, V, etc., and is necessary as a tool at room temperature and high temperature. It is extremely effective in improving wear resistance. If C is less than 1.0%, the number of double carbides produced is small, the hardness is too low, and the desired performance cannot be obtained.

However, if C is contained in a large amount exceeding 4.0%, the toughness is reduced, so the content range is set to 1.0 to 4.0%.

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%, the effect will be small, and if it is added too much beyond 35%, the double carbide will become coarse and brittle, so O W + 10.0 to 25 was set to 25.0-35.0%. It combines with .0% w#-ic to form a hard carbide and is normally IVi.
! It is also effective in increasing high-temperature hardness, improving wear resistance, and increasing cutting durability. However, if added in too large a quantity, the toughness will decrease and cracks will occur due to topping, so the content was set at 10.0 to 25.0%.

Co: 35.0 to 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, so 55. 0%~65.
It was set to 0%.

REM, Y, Se, Hf: Q, 001~0
．． 6% REM (La, Ce, Pr, Nd, s
m, others).

Y and Sc have the effect of dispersing carbides extremely finely and uniformly, and are effective in improving toughness and wear resistance. However, if added in large quantities, the toughness will decrease, so 0.00
The range was 1 to 0.6%.

Si: 0.03 to 6.0% St is also added as a deoxidizing agent, but it strengthens the solid matrix, lowers the yield point, prevents surface oxidation at high temperatures, and improves the fatigue limit.

If added in a large amount, it is effective in refining carbides.

However, if added vertically, the tool life will be shortened due to a decrease in thermal conductivity and toughness, so 0.
The range was 03 to 6.0 inches.

Mn: 0.05-10%, Ns: 0.01-1
5.0% Mn and Ni are both 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%, M'o: 0.0
5-15.0%.

'1411: o, 1 ~ 15.0%, T&: 0
．． 1 to 10.0% V, Mo, and Nb all form carbides 1 and greatly contribute to improving wear resistance and increasing strength.

However, if too large a quantity is added, the composite carbon becomes coarse and brittle, so each component should be within the above-mentioned range.

Tl: 0.01-0.5%, Zr: 0
．． 01-[1,5%, At: 0.1-0.5%.

N: 0.02-015%, B: 0.005-0.8%T
i, Zr+A4N+B are all elements that contribute to improving toughness, and Ti, Zr, and A4N have the effect of making the crystals It, finer. The shredded B suppresses the precipitation of pro-eutectoid carbides at austenite grain boundaries during the quenching and cooling process. However, when added in large amounts, Ti, Zr, A
Since 1 and N increase non-metallic inclusions, and B causes brittleness due to the formation of multiple lobes of borides, each was set within the above range.

Next, the features of the present invention will be explained with reference to examples.

Example Table M1 shows the chemical composition of the test materials of the invention steel and comparative steel.

An alloy having the chemical composition of the 11 citrons shown in Table 1 was cast into a graphite mold to create a bending test sample of 5+xi$X80 and a casting tool of 10 out of 10 x 80.

Second, each sample was subjected to a static bending test in casting 1 and the toughness was compared, and it was found that the steel of the present invention has higher toughness than the comparative steel.

Second Narrow Toughness Test Results Table 3 shows the results of cutting performance tests conducted on the cast bits of each sample.

In addition, in the cutting performance test, HB145 S was used as the rigid material.
Cutting speed f of US 27 M (fl 701111)
60m/nr test.

Cutting was performed under the conditions of 1 depth of cut and 1.08 mm of feed, and the cutting durability time at this time was determined.

The cutting tool used for the first cutting is still in a cast condition.

As a result, it can be seen that the alloy of the present invention has superior machinability.

Note that the tool bit used in this example was cast.
Furthermore, heat treatment may be performed for the purpose of improving durability.

-11J- Table 6 Cutting performance test results As explained above, the alloy for 1-manufactured tools of the present invention has RE
By adding M, Y, Sc, or Hf, the carbon particles are significantly refined to improve toughness, wear resistance, cutting durability, etc. required for tools, and are suitable for cutting tools, molds, punches, etc. It shows excellent performance not only as a single tool but also as a weld overlay tool.

= 11- Requester: Yoshio Kawaguchi, representative of the Daido Special Steel Law Company, procedural amendment (voluntary) July 28, 1980 Commissioner of the Japan Patent Office Shima 1) Tono Haruki 1, Patent application for indication of the case 1982- 100455 No. 2, Title of the invention 6, Relationship with the case of the person making the amendment Applicant name C5711 Daido Steel Co., Ltd. Takeda Ki
Representative: Kizo Takeda 4, Agent: 105-5, Date of amendment order: 1920, month, day, Japanese Patent Publication No. 81158-3943 (6) (1) Page 6 of the specification, second line from the end rY, SC
`` is corrected as ry, sc, af.

(2) Page 8, line 1 of the specification, “V, Me, Nb are” r V, Mo, Nb, Ta are”
and correct it.

(3) Table 1 on page 9 of the specification shall be amended as a separate sheet.

that's all

Claims (1)

[Claims] (1) REM, Y, S e, H for alloys for casting tools
An alloy for a casting tool, characterized in that it contains o, ooi to 0.6% of one or more f.