JPH02232302A - Manufacture of powder high alloy steel rolled material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing rolled materials such as bars or wires from powdered high-alloy steel. Conventional technology Conventionally, when obtaining rolled materials such as high-speed tool steel bars or wire rods using powder manufacturing methods, powdered high-speed tool steel is first filled into a metal sheathed can and then heated under high temperature and high pressure. After sintering, the metal sheath adhering to the surface of the sintered body is removed by cutting it with a lathe, etc., and then forging is performed, or after the sintered body is forged, the metal sheath can adhering to the surface is removed. The metal sheathed can is removed by polishing it with a grinder.
The forged material from which the metal sheath has been removed is then rolled to a predetermined size and straightened to obtain the desired rolled material. Problems to be Solved by the Invention However, since high-alloy materials such as high-speed tool steel have poor workability, when obtaining rolled materials using conventional methods, there is a problem that cracks occur on the surface of the rolled materials. Another problem was that it was difficult to perform drawing processing when obtaining thin wood. Furthermore, there is a problem that the processed material often breaks during the straightening process, and therefore the straightening process has to be carried out under heating. The present invention has been made in view of the above-mentioned problems in the conventional technology. Therefore, an object of the present invention is to provide a method for manufacturing a powdered high alloy steel rolled material that does not generate scratches due to cracks on the surface during rolling and does not break during the straightening process. Means and Effects for Solving the Problems As a result of study, the inventor has determined that the removal of the metal sheath can by grinding or cutting, which was conventionally performed before or immediately after forging,
We have discovered that the above-mentioned problems with conventional technology can be solved if this is done in the final processing step before commercialization, and we have completed the present invention. That is, the method for producing rolled powdered high-alloy steel material of the present invention involves sintering powdered high-alloy steel filled in a metal sheathed can under high temperature and high pressure, and then forging the resulting forged material. , the metal sheathed can is attached by rolling or rolling and drawing with the metal sheath still attached to the surface, straightening the resulting processed material, and then grinding or cutting the surface. It is characterized by removing sheath can residue. The present invention will be explained in detail below. The powdered high alloy steel used in the present invention may be any conventionally known steel.
The particle size is usually preferably in the range of 0.2 to 3 fi. After filling a metal sheathed can with powdered high-alloy steel and sealing it, the can is sintered under high temperature and pressure using a conventional method, and then forged to obtain a forged material. This forged material has a metal sheath attached to its surface. The obtained forged material is heated to a predetermined temperature and annealed, and then rolled to a predetermined cross-sectional size. When obtaining a bar, it is rolled to a predetermined cross-sectional size,
After annealing the obtained bar material, it is processed in a straightening process to correct the bends caused by rolling. After straightening, grinding or cutting is performed to remove metal sheath can residue remaining on the surface, and the product is made into a bar product. In addition, when obtaining thin material, after obtaining a coil material having a predetermined cross-sectional size by rolling, drawing is performed, and the obtained wire material is annealed, and then processed in a straightening process to correct the bending caused by drawing. Also, cut it to the specified length. The surface of the cut wire rod is polished using, for example, a centerless grinder to remove the metal sheath can residue remaining on the surface, and the wire rod is made into a thin wire product. The present invention operates as follows because the metal sheath can is attached to the outer surface of the sintered body until the final processing step. 1) The cooling rate of the sintered body is moderated by the presence of the metal sheath can. In other words, the effect of preventing supercooling occurs. Therefore, the suitable processing temperature range for powdered high-alloy steel sintered bodies, which have poor workability, is expanded compared to conventional methods. 2) During the straightening process, the metal sheath can residue adhering to the surrounding area acts as a protective material to prevent the rolled material from breaking. 3) When obtaining fine lumber, the adhering metal sheath can residue acts as a lubricant during drawing, making the drawing process smooth. 4》Prevents the surface of the forged or rolled material from being oxidized during heat treatment such as forging or rolling, and also removes any metal sheath can residue that may have adhered due to polishing or grinding immediately before the final product is obtained. Since it is removed, product yield is improved. Examples The present invention will be explained by examples. Example I C2.1%, Cr4.0%, Mo6.0%, W14. O
%, ■ 5.5%, Co 12.0%, balance Fe (all % is weight %) powder of high speed tool steel is filled into a mild steel sheathed can and sealed, Sintered at high temperature under high pressure to obtain a sintered body of 450 maφ,
The forged material was then subjected to a vi heat treatment at 1140°C to obtain a forged material having a cross section of 94 x 94 m. This forged material was annealed at 860°C and rolled at 1180°C to obtain a bar having a cross section of 20 mm. After straightening the obtained bar material, beering is performed using a lathe to remove the soft @ that has adhered to the surface.
The sheath can residue was removed to obtain a bar product with a cross section of 19lφ. In the above case, no scratches due to cracks occurred on the surface of the bar during rolling. In addition, the camellia wood was not broken during the straightening process, and the bar material could be produced efficiently. Example 2 A forged material having a cross section of 94 x 94M was obtained in the same manner as in Example 1. After annealing in the same manner as in Example 1, a coil material having a cross section of 9flφ was obtained by rolling at 1180°C. After further annealing at 860°C, drawing was performed at 800°C to obtain an 8.5 mm diameter.
A wire rod having a cross section of Next, this wire rod was treated with a centerless grinder to remove the residue of the mild steel sheath can attached to the surface, and a wire rod product having a cross section of 8.3 φ was obtained. In this example, as in Example 1, no scratches due to cracks were generated on the surface of the coil material during rolling. In addition, the wire rod did not break during the straightening process, and the wire rod could be manufactured efficiently. Effects of the Invention As described above, the present invention has the following excellent effects because the rolling process or the rolling process, the drawing process, and the straightening process are performed with the metal sheath can attached to the outer surface of the sintered body. occurs.

1) In the heat treatment, the cooling rate of the sintered body is relaxed, so the suitable processing temperature range for the powdered high-grade metal a sintered body, which has poor workability, is expanded compared to the conventional method. 2》Breakage of the processed material is prevented during the straightening process. 3》When obtaining fine lumber,
The drawing process can be carried out smoothly. 4) During heat treatment such as forging and rolling, oxidation of the surface of @formed material or rolled material is prevented, improving product yield. Patent applicant: Daido Steel Co., Ltd., patent attorney: Tsuyoshi Watanabe

Claims (1)

[Claims] (1) Powdered high alloy steel filled in a metal sheath can,
The forged material obtained by sintering under high temperature and high pressure and then forging is rolled with the metal sheath still attached to the surface, or the processed material is obtained by rolling and drawing. 1. A method for producing a powdered high-alloy steel rolled material, the method comprising: removing adhering metal sheath can residue by grinding or cutting the surface after the straightening.