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Steel for high-strength bolt and application thereof

A technology of high-strength bolts and high-strength bolts, which is applied in the field of steel for bolts, can solve problems such as difficulty in balancing strength and cold heading performance, and affect safety in use, and achieve excellent comprehensive performance, excellent cold heading performance, and excellent delayed fracture resistance. Effect

Inactive Publication Date: 2018-12-07
湖南铂固科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existing materials for bolts are difficult to balance in terms of strength and cold heading performance, which affects the safety of use

Method used

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  • Steel for high-strength bolt and application thereof
  • Steel for high-strength bolt and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A steel for high-strength bolts, comprising the following components by mass percentage: 0.33% carbon, 1.7% silicon, 0.25% manganese, phosphorus ≤ 0.015%, sulfur ≤ 0.003%, titanium 0.05%, aluminum 0.05%, chromium 0.75% , nickel 0.6%, molybdenum 0.18%, niobium 0.07%, and the balance is iron and unavoidable impurities.

[0019] When utilizing the above-mentioned steel for high-strength bolts to prepare high-strength bolts (the specifications are M8*30mm (diameter*length)), first the steel for high-strength bolts is obtained by ironmaking, steelmaking, and hot rolling to obtain wire rods, and then through spheroidization, It can be obtained by descaling, wire drawing, cold heading, quenching, tempering and oiling. The specification of the finally prepared bolt is 8*30mm. Among them, the spheroidizing treatment is treated at 750°C for 5 hours, the descaling is treated in acid solution, the quenching treatment is treated at 890°C for 60 minutes, the quenching medium is supe...

Embodiment 2

[0021] A steel for high-strength bolts, comprising the following components by mass percentage: 0.35% carbon, 1.3% silicon, 0.3% manganese, phosphorus ≤ 0.015%, sulfur ≤ 0.003%, titanium 0.09%, aluminum 0.04%, chromium 0.05% , nickel 1.0%, molybdenum 0.15%, niobium 0.05%, and the balance is iron and unavoidable impurities.

[0022] In this embodiment, the method for preparing high-strength bolts (with a specification of M8*30mm) from steel for high-strength bolts is the same as that in Embodiment 1. The finally prepared bolts had a size of 8*30mm, and were tempered at 380°C to obtain sample B1, and tempered at 425°C to obtain sample B2.

Embodiment 3

[0024] A steel for high-strength bolts, including the following components in terms of mass percentage: 0.36% carbon, 1.3% silicon, 0.6% manganese, phosphorus ≤ 0.015%, sulfur ≤ 0.003%, titanium 0.09%, aluminum 0.04%, chromium 0.05% , nickel 0.8%, molybdenum 0.18%, niobium 0.05%, the balance is iron and unavoidable impurities.

[0025] In this embodiment, the method for preparing high-strength bolts (with a specification of M8*30mm) from steel for high-strength bolts is the same as that in Embodiment 1. The finally prepared bolts have a specification of 8*30mm, and tempered at 380°C to obtain sample C1, and tempered at 425°C to obtain sample C2.

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Abstract

The invention discloses steel for a high-strength bolt. The steel comprises the following components of, by mass percent, 0.2-0.45% of carbon, 1.2-2.5% of silicon, 0.2-1.5% of manganese, less than orequal to 0.002% of phosphorus, less than or equal to 0.004% of sulfur, 0.02-0.10% of titanium, 0.02-0.2% of aluminum, 0.05-1.5% of chromium, 0.5-1.05% of nickel, 0.15-0.25% of molybdenum, 0.02-0.1% ofniobium and the balance iron and unavoidable impurities. The invention also correspondingly provides an application of the steel for the high-strength bolt. By adjusting the composition of the high-strength bolt and the amounts of the components, the components play synergistic effect mutually, and the finally obtained high-strength bolt has high comprehensive performance such as high strength, outstanding cold heading performance, outstanding and delayed fracture resistance. Fasteners such a bolt and a screw which are made of the steel for the high-strength bolt also have excellent comprehensive performance.

Description

technical field [0001] The invention belongs to the technical field of high-strength fasteners, and in particular relates to steel for bolts and its application. Background technique [0002] Fastener is a widely used mechanical part, which is widely used in vehicles, ships, railways, bridges and buildings. Fasteners are the basic parts of the mechanical industry and are in great demand. Fasteners include various bolts, riveting joints, nuts, rivets, etc. According to relevant standards, bolt performance grades are divided into more than 10 grades such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, among which bolts of grade 8.8 and above are made of low carbon alloy steel or medium carbon steel and after heat treatment The resulting bolts are commonly referred to as high-strength bolts, and the rest are commonly referred to as ordinary bolts. [0003] Since bolts are used for the connection of various structural materials, they need to bear a lot of pressure and shear ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/50C22C38/06C22C38/44C22C38/48C21D1/32C21D1/18C21D9/00
CPCC22C38/02C21D1/18C21D1/32C21D9/0093C22C38/04C22C38/06C22C38/34C22C38/44C22C38/48C22C38/50
Inventor 叶振宇
Owner 湖南铂固科技股份有限公司
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