Tensile fracture determining method for crack forming period of steel and iron material

A technology for steel materials and determination methods, which is applied in the analysis of materials, the use of stable tension/pressure to test the strength of materials, and the preparation of samples for testing. Effect

Active Publication Date: 2018-06-19
BEIJING BEIYE FUNCTIONAL MATERIALS CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for judging the tensile fracture of steel material crack formation period, which solves the problem that the traditional metallographic observation method cannot accurately determine the specific period of crack formation

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  • Tensile fracture determining method for crack forming period of steel and iron material
  • Tensile fracture determining method for crack forming period of steel and iron material

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Embodiment 1

[0019] Take a crack inside a Q345D bar with a specification of Φ250mm as an example. The crack was found during low-magnification inspection. In order to protect the appearance of the crack, clean anti-rust oil was dripped on the crack to isolate air and water, and wrapped with tape Prevent the loss of anti-rust oil. A tensile sample containing cracks is processed at the crack. The thickness of the tensile sample is 5mm and the length is 150mm. It is stretched at room temperature on a computer-controlled electronic universal testing machine. In order to ensure that the sample breaks along the crack, the beam of the tensile testing machine The displacement speed was set at 0.01 mm / min until the sample fractured along the crack, and the two crack surfaces were mechanically separated without destroying the original morphology of the crack surface. In order to prevent the broken fracture from being oxidized or corroded by long-term contact with air, dust and water, the fracture sh...

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Abstract

The invention relates to a tensile fracture determining method for a crack forming period of a steel and iron material, which belongs to the technical field of failure analysis of a steel and iron material. The method comprises the following steps: firstly preparing a tensile sample comprising cracks, performing the breaking test, separating two crack surfaces, and determining the crack forming period according to characteristics of the existence of dimples of a micro-morphology of a fracture, cleavage, quasi-cleavage or intergranular fracture and the like. The method has the advantages that compared with the existing metallographic observation method, the tensile fracture analysis method does not damage the morphology of the crack and micro-tissues nearby the crack, so that the determination accuracy of the crack forming period can be improved, and the important evidence can be provided for analyzing the forming reason of the crack and making the preventive measures.

Description

technical field [0001] The invention belongs to the technical field of failure analysis of iron and steel materials, and in particular relates to a method for judging tensile fractures in the crack formation period of iron and steel materials. In particular, the invention relates to a method for judging the crack formation period of a ferrite pearlite steel material. Background technique [0002] Ferritic pearlitic iron and steel materials generally mean that the structure of the steel is ferrite + pearlite below about 600 ° C, and the transformation of "austenite → ferrite + pearlite" occurs at about 600 ~ 800 ° C, and at about 800 ° C ~1200℃ is austenite. Cracks are common defects in ferritic pearlite steel materials, and cracks are most likely to form in two periods: one is in the austenite before the transformation of "austenite → ferrite + pearlite" begins, and the other is in the In the ferrite and / or pearlite after the start of the "austenite → ferrite + pearlite" t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/08G01N3/06G01N1/34
CPCG01N1/34G01N3/06G01N3/08
Inventor 文新理章清泉李振瑞张荣李丽敏王超曹宇吴会云魏然
Owner BEIJING BEIYE FUNCTIONAL MATERIALS CORP
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