Method of producing forgings having excellent tensile strength and elongation from steel wire rods

a technology of tensile strength and elongation, which is applied in the direction of manufacturing tools, furnaces, heat treatment equipment, etc., can solve the problems of difficult to produce such screws, many manufacturers do not produce screws of the highest grade of tensile strength, and it is difficult for heat to spread uniformly from the inner to the outer parts of the steel, so as to achieve high degree of toughness and hardness

Inactive Publication Date: 2008-10-23
FWU KWANG ENTERPRISES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0018]Therefore, the object of the present invention is to provide a method of producing forgings that have a tensile strength of up to 160 kgf / mm2and an elongation of up to 16˜21%, and that also have a high degree of toughness and hardness.

Problems solved by technology

However, due to the limitations encountered when using old materials and old manufacturing methods, it is difficult to produce such screws.
Hence, many manufacturers do not produce screws of the highest grade of tensile strength.
Thus, the larger the dimensions, the more difficult it is for the heat to spread uniformly from the inner to the outer parts of the steel.
Hence, it is difficult for the forgings 2 with large dimensions to achieve the tensile strength of 140 kg / mm2, so that the resulting products have insufficient hardness and mechanical properties.

Method used

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  • Method of producing forgings having excellent tensile strength and elongation from steel wire rods
  • Method of producing forgings having excellent tensile strength and elongation from steel wire rods
  • Method of producing forgings having excellent tensile strength and elongation from steel wire rods

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Embodiment Construction

[0025]FIG. 3 illustrates the steps involved in a method of producing forgings 4 that have a tensile strength of up to 160 kgf / mm2 and an elongation of up to 16˜21% according to the preferred embodiment of the present invention. These steps will be described in greater detail below.

[0026]In step (a), an alloy steel wire rod 3 is subjected to a first spheroidized annealing process at a temperature range of 680˜700° C., which is lower than the phase transformation temperature of the alloy steel wire rod 3. The wire rod 3 is made of a hardened wire material selected from the group consisting of nickel-chromium-molybdenum steel, such as SNCM439, and chromium-molybdenum steel, such as SCM445H (SAE4145H), SCM445, SCM440, or SCM440H. In this embodiment, the wire rod 3 is made of SNCM439 (JIS G4103; nickel-chromium-molybdenum steel corresponding to AISI 4340, SAE4340) with a chemical composition of 0.36˜0.43% C; 0.15˜0.35% Si; 0.60˜0.90% Mn; 1.60˜2.00% Ni; 0.60˜1.00% Cr; and 0.15˜0.30% Mo. T...

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Abstract

A method of producing forgings includes the steps of: forming forgings from a steel wire rod; heating the forgings to a temperature range of 830˜900° C.; subjecting the forgings to first tempering at a temperature range of 100˜300° C. after the heating at 830˜900° C.; and subjecting the forgings to second tempering at a temperature range of 300˜400° C, after the first tempering. In the first tempering, the forgings are quenched in a salt bath having a temperature in the range of 100˜300° C., and are tempered for 60˜130 minutes. In the second tempering, the forgings are quenched in a salt bath having a temperature in the range of 300—400° C., and are tempered for 30˜150 minutes.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention relates to a method of producing forgings from steel wire rods, more particularly to a method of producing forgings from steel wire rods, in which the forgings have a tensile strength of up to 160 kgf / mm2 and an elongation of up to 16-21%.[0003]2. Description of the Related Art[0004]CNS3934 of the Chinese National Standards (CNS) specifies the standard properties that forgings should have. The highest grade of tensile strength for strong screws is 140 kgf / mm2. However, due to the limitations encountered when using old materials and old manufacturing methods, it is difficult to produce such screws. Hence, many manufacturers do not produce screws of the highest grade of tensile strength.[0005]In light of the aforementioned standard for strong screws, a method of producing screws that have the highest tensile strength has been developed by the applicant, and is disclosed in Taiwanese Patent No. I254656, title...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): C21D9/52C21D9/00
CPCC21D1/20C21D1/26C21D1/32C21D6/004C21D7/02C21D9/0075C21D9/0093C21D2211/002C21D2211/008
InventorCHANG, YUN-TE
OwnerFWU KWANG ENTERPRISES