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A Method for Determining the Stress Relief Annealing Temperature of Cold-Formed Thick-walled Sections

A technology of stress relief annealing and annealing temperature, which is applied in the direction of measuring force, testing material hardness, preparation of test samples, etc., which can solve problems such as stress not being eliminated, affecting static load strength, fatigue strength and stability of bending corners. , to achieve the effect of reducing energy consumption

Active Publication Date: 2021-09-03
WUHAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This shows that the residual stress at the corner has not been eliminated, which seriously affects the static load strength, fatigue strength and stability of the corner of the research object

Method used

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  • A Method for Determining the Stress Relief Annealing Temperature of Cold-Formed Thick-walled Sections
  • A Method for Determining the Stress Relief Annealing Temperature of Cold-Formed Thick-walled Sections
  • A Method for Determining the Stress Relief Annealing Temperature of Cold-Formed Thick-walled Sections

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Embodiment 1

[0048] 1. A method for determining the stress-relieving annealing temperature for corners of cold-formed thick-walled section steel. The steps of the method described in this embodiment are:

[0049] The cold-formed thick-walled section steel described in this embodiment is a closed cold-formed section steel, the cross-sectional shape of the cold-formed thick-walled section steel is square, and the wall thickness t=10mm of the cold-formed thick-walled section steel; the material of the cold-formed thick-walled section steel is low carbon alloy steel.

[0050] Step 1. Select 9 cold-formed thick-walled section steels produced in the same batch with the specification of H×B×t=200×200×10 mm as original samples.

[0051] Step 2. Select an original sample, such as figure 1 As shown, taking the weld as the axis of symmetry, select 5 points to be measured on the outer surface near the upper bend and the outer surface near the lower bend on one side of the symmetry axis, and the 5 po...

Embodiment 2

[0079] A method for determining the annealing temperature for corner stress relief of cold-formed thick-walled steel. The steps of the method described in this embodiment are:

[0080] The cold-formed thick-walled steel described in this embodiment is a closed cold-formed steel, the cross-sectional shape of the cold-formed thick-walled steel is rectangular, and the wall thickness t=12mm of the cold-formed thick-walled steel; the material of the cold-formed thick-walled steel is low carbon alloy steel.

[0081] Step 1. Select 15 cold-formed thick-walled section steels produced in the same batch with the specification of H×B×t=500×300×12mm as original samples.

[0082] Step 2. Select an original sample, take the weld as the axis of symmetry, and select 5 points to be measured on the outer surface near the upper corner and the outer surface near the lower corner on one side of the axis of symmetry. The points to be measured are located on the same cross section.

[0083] The m...

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Abstract

The invention relates to a method for determining the stress-relief annealing temperature of cold-formed thick-walled section steel. The technical scheme is: cut the original sample into the corner, take 5 equal points on the outer surface of the corner, prepare a metallographic sample before annealing, and conduct metallographic structure observation and hardness measurement. Prepare the metallographic samples after annealing at each annealing temperature point, observe the metallographic structure and measure the hardness of the metallographic samples after annealing, take the samples after annealing that satisfy both hardness conditions and recrystallization, and obtain the samples that meet the requirements of recrystallization The sample after annealing; the lowest annealing temperature among the annealing temperatures marked on the sample after annealing that satisfies recrystallization is the minimum annealing temperature that meets recrystallization, and the minimum annealing temperature that satisfies recrystallization minus 10-20°C is Stress relief annealing temperature. The invention can accurately determine the stress-relieving annealing temperature of the corner of the cold-formed thick-walled section steel, and can ensure that the outer surface and internal residual stress of the corner of the cold-formed thick-walled section steel are completely eliminated.

Description

technical field [0001] The invention belongs to the technical field of stress relief annealing for corners of cold-formed thick-walled section steel. In particular, it relates to a method for determining the annealing temperature for corner stress relief of cold-formed thick-walled section steel. Background technique [0002] The residual stress at the corner of cold-formed steel affects the static load strength, fatigue strength and stability of the component, and accelerates the brittle fracture and corrosion cracking of the component. Eliminating residual stress can greatly improve its performance and expand its application range, so that the product can be used in high-end and major projects. [0003] Stress relief annealing is to eliminate the residual internal stress in the machined workpiece to improve dimensional stability and prevent deformation and cracking of the workpiece. Before finishing or quenching, the workpiece is heated to a temperature below Ac1, kept fo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N25/00G01N25/14G01N3/40G01N1/28G01N21/84G01L1/25G01L5/00C21D1/30
CPCC21D1/30G01L1/25G01L5/0047G01N1/28G01N1/286G01N3/40G01N21/84G01N25/00G01N25/147G01N2001/2873G01N2021/8477
Inventor 胡盛德姜屹楠郑一鸣李立新夏俊翔
Owner WUHAN UNIV OF SCI & TECH