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Processing method for stainless steel high-strength bolt

A technology of high-strength bolts and processing methods, which is applied in the field of processing stainless steel high-strength bolts, can solve problems such as poor impact toughness, high processing cost, and rod fracture, achieve strong impact toughness and yield strength, and reduce processing cycles , the effect of increasing the intensity of use

Active Publication Date: 2013-04-03
GUIZHOU JINGLI HANGTAI TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a processing method for high-strength stainless steel bolts, so as to solve the problem of U-turn, rod fracture, poor impact toughness, low yield strength, and poor processing due to brittle fractures in high-strength bolts processed by traditional processing methods. Difficult quality control, low precision and high processing costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1: When it is necessary to process high-strength bolts with thread specifications less than or equal to M8, the precipitation-hardening stainless steel 0Cr13Ni8Mo2Al is first blanked according to the bolt size, and the blank after blanking is copper-plated and lubricated, and then put into the upsetting mold to heat the bolts For the head type, the workpiece is subjected to solid solution treatment in a vacuum or inert gas furnace at 930±25°C for 2 hours, and then cooled with nitrogen at a temperature of -73°C for 2 hours, and the oxide scale on the cooled workpiece surface is removed by sandblasting. The diameter of the thread rolling blank is processed by shrinking rod processing, and the aging treatment is performed at 480°C for 4 hours, and then the stress is relieved at 195°C for 12 hours, and the centerless grinding is used to polish the workpiece rod and the thread blank diameter. , the RP18E CNC thread rolling machine produced by Italian ORT company was s...

Embodiment 2

[0027] Example 2: When high-strength bolts with thread specifications between M8 and M24 need to be processed, the precipitation-hardening stainless steel 0Cr13Ni8Mo2Al is first blanked according to the bolt size, and the blank after blanking is copper-plated and lubricated, then put into the upsetting mold for heating Upsetting the bolt head shape, the workpiece is subjected to solid solution treatment in a vacuum or inert gas furnace at 967±25°C for 3 hours, then cooled with nitrogen at a temperature of -73°C for 2 hours, and sandblasting to remove oxidation on the surface of the cooled workpiece After peeling, the diameter of the thread rolling blank is processed by shrinking rod processing, and the aging treatment is carried out at 480°C for 4 hours, and then the stress is relieved at 195°C for 12 hours. For polishing and grinding, the RP24E CNC thread rolling machine produced by Italian ORT company is used to roll the thread and the arc R of the connection between the supp...

Embodiment 3

[0028] Example 3: When it is necessary to process high-strength bolts with thread specifications between M24 and M42, the precipitation hardening stainless steel 0Cr13Ni8Mo2Al is first blanked according to the bolt size, and the blank after blanking is copper-plated and lubricated, then put into the upsetting mold for heating Upsetting the bolt head shape, the workpiece is solid solution treated in a vacuum or inert gas furnace for 3.5 hours at 985±25°C, and then cooled with nitrogen at a temperature of -73°C for 2 hours, and the oxidation on the surface of the cooled workpiece is removed by sandblasting After peeling, the diameter of the thread rolling blank is processed by shrinking rod processing, and the aging treatment is carried out at 480°C for 4 hours, and then the stress is relieved at 195°C for 12 hours. For polishing and grinding, the RP30E CNC thread rolling machine produced by Italian ORT company is used to roll the thread and the arc R of the connection between th...

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Abstract

The invention discloses a processing method for a stainless steel high-strength bolt. The method comprises blanking, lubricating, thermal heading, solution treatment, cooling, descaling, processing of diameter of a threaded rolled thread billet, aging treatment, polishing, rolling of a thread and an arc at the connection part of a head part and a rod, flaw detection, cleaning and passivating. According to the method, precipitation hardening stainless steel is taken as a part blank, the head part is formed in one step through thermal heading, the processing period is greatly shortened, the diameter of the thread billet is processed by a shortening rod, the thread is rolled after aging treatment, the use strength of a thread part of a product is improved, flaw detection is carried out after thread rolling, a cracked product resulting from procedures like thermal heading, thermal treatment and thread rolling is prevented from going to the procedures like assembly and use as well as rolling of the arc R below a bolt head, so as to improve the connection strength of the head part and the rod part of the product, the strength of the bolt is greatly enhanced, and the fabricated part has relatively strong impact toughness and yield strength.

Description

technical field [0001] The invention belongs to the technical field of mechanical manufacturing, in particular to a processing method for stainless steel high-strength bolts. Background technique [0002] In the standard parts of aviation, aerospace, high-speed rail and other industries, high-strength bolts are fasteners that are often assembled and used under conditions of high strength requirements and harsh working environments (such as high vibration, high air humidity, large temperature difference, etc.). At present, China generally uses medium-carbon low-alloy ultra-high-strength steel to make high-strength bolts (σb≥1500MPa), which are prone to brittle fracture under high stress during use, that is, hydrogen embrittlement can easily lead to unsafe phenomena such as bolt turning and rod fracture. The appearance of the bolt; and the processing technology of the bolt generally adopts cold heading forming. In order to improve the strength of the part, the raw material nee...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23P15/00
Inventor 王相波林燚刘清树何春林陈春旭
Owner GUIZHOU JINGLI HANGTAI TECH
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