Structural steel with yield strength of 345MPa and high fatigue strength as well as manufacturing method of structural steel

A manufacturing method and technology for structural steel, applied in the field of iron and steel smelting, can solve problems such as increased cost and increased fatigue strength, and achieve the effects of increasing energy storage, improving fatigue performance, and being beneficial to fatigue performance

Inactive Publication Date: 2019-10-22
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It solves the problem of cost increase caused by increasing the strength and fatigue strengt...

Method used

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  • Structural steel with yield strength of 345MPa and high fatigue strength as well as manufacturing method of structural steel
  • Structural steel with yield strength of 345MPa and high fatigue strength as well as manufacturing method of structural steel
  • Structural steel with yield strength of 345MPa and high fatigue strength as well as manufacturing method of structural steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045]A yield 345MPa high-fatigue structural steel and its manufacturing method provided in this example, the chemical composition and mass percentage are as follows: C: 0.14%, Mn: 1.30%, Nb: 0.028%, Alt: 0.022%, Ti: 0.003% , Si: 0.07%, P: 0.008%, S: 0.005%, and the balance is iron and unavoidable impurities.

[0046] The thickness of the slab is 150mm, the heating temperature is 1145°C, the heating rate is 8min / cm according to the thickness of the slab, the total time is 120min, and the soaking time is 30min;

[0047] Odd-pass rolling is adopted, the thickness of the finished product is 6mm, and the thickness of the billet to be warmed is set to 7.0 times the thickness of the finished product;

[0048] The starting temperature of the finishing rolling is controlled at 1020°C, and the total rolling passes are 13 passes, of which the last 3 passes of the finishing rolling have a cumulative deformation of 45%, and the deformation of the last pass is 12%. The finishing rolling te...

Embodiment 2

[0051] A high-fatigue structural steel with a yield of 345MPa and its manufacturing method provided in this embodiment, the chemical composition and mass percentage are as follows: C: 0.13%, Mn: 1.52%, Nb: 0.025%, Alt: 0.020%, Ti: 0.004% , Si: 0.12%, P: 0.010%, S: 0.003%, and the balance is iron and unavoidable impurities.

[0052] The thickness of the slab is 220mm, the heating temperature is 1130°C, the heating rate is 10min / cm according to the thickness of the slab, the total time is 220min, and the soaking time is 45min;

[0053] Odd-pass rolling is adopted, the thickness of the finished product is 12mm, and the thickness of the billet to be warmed is set to 4.0 times the thickness of the finished product;

[0054] The starting temperature of the finish rolling is controlled at 1020°C, and the total rolling passes are 11 passes, of which the last 3 passes of the finish rolling have a cumulative deformation of 46%, and the deformation of the last pass is 12%. The finishing ...

Embodiment 3

[0057] A high fatigue structural steel with a yield of 345MPa and its manufacturing method provided in this embodiment, the chemical composition and mass percentage are as follows: C: 0.16%, Mn: 1.55%, Nb: 0.035%, Alt: 0.021%, Ti: 0.003% , Si: 0.07%, P: 0.008%, S: 0.004%, and the balance is iron and unavoidable impurities.

[0058] The thickness of the slab is 220mm, the heating temperature is 1150°C, the heating rate is 9min / cm according to the thickness of the slab, the total time is 198min, and the soaking time is 60min;

[0059] Odd pass rolling is adopted, the thickness of the finished product is 22mm, and the thickness of the billet to be warmed is set to 3.2 times the thickness of the finished product;

[0060] The starting temperature of the finish rolling is controlled at 980°C, and the total rolling passes are 11 passes, of which the last 3 passes of the finish rolling have a cumulative deformation of 43%, and the deformation of the last pass is 11%. The finishing ro...

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Abstract

The invention discloses a structural steel with yield strength of 345MPa and high fatigue strength as well as a manufacturing method of the structural steel and relates to the technical field of ironand steel smelting. The structural steel comprises the following chemical components by mass: 0.13%-0.16% of C, 1.30%-1.60% of Mn, 0.020%-0.050% of Nb, 0.020%-0.030% of Alt, <= 0.010% of Ti, <= 0.12%of Si, <= 0.010% of P, <= 0.005% of S and the balance being Fe and unavoidable impurities. The common alloying element Nb is added and a high-pressure rolling process is used, so as to give full playto the effects of dispersion strengthening and grain refinement; and therefore, the fatigue property of the material is improved and good comprehensive mechanical properties and good surface quality are achieved. The problem of the cost increase, caused by improving the strength of steel to improve the fatigue strength of the steel, is solved; and the manufacturing method reduces the production costs of downstream enterprises and is an economic production mode.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a high-fatigue structural steel with a yield of 345MPa and a manufacturing method thereof. Background technique [0002] In construction machinery products, welded structural parts account for about 50%-70% of the weight of the whole machine, and the main steel materials used are carbon steel and low-alloy structural steel, mainly with a yield of 345MPa. Most construction machinery and equipment work in the field, the working environment is harsh, the working conditions are very complicated, and they bear complex and variable cyclic loads, which are easy to cause fatigue damage. Since structural parts have no obvious plastic deformation and cracks are not easy to detect when fatigue damage occurs, the sudden damage is a very dangerous fracture. In order to ensure the safety of use, the life of construction machinery has strict deadlines and scrapping requirements....

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14C21D8/02C22C33/04
CPCC21D8/0205C21D8/0226C21D8/0263C22C33/04C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14
Inventor 李明潘中德冯勇王福明弓硕王凡
Owner NANJING IRON & STEEL CO LTD
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