Title:
1400 MPA GRADE DELAYED-FRACTURE-RESISTANT HIGH-STRENGTH BOLT AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2021/027402
Kind Code:
A1
Abstract:
A 1400 MPa grade delayed-fracture-resistant high-strength bolt and a manufacturing method therefor. The chemical elements thereof contain alloy elements such as Mo, Cu and V; by means of a treatment method of high-temperature quenching and two-stage tempering, copper-rich phase ε-Cu and fine second phase particles such as VC and Mo2C are fully dispersed and precipitated in a tempering matrix structure, so that a bolt has high delayed-fracture-resistant performance and corrosion-resistant performance when the strength grade of the bolt reaches 1400 MPa. According to the high-strength bolt, the precipitated phase action of the alloy element Cu and the precipitated phase action of special carbon compounds and nitrogen compounds formed by Mo, V, Nb, Ti, etc., are fully used, so that the tensile strength of the bolt is between 1445 MPa and 1510 MPa, the percentage reduction of area is 50-56％, the elongation after fracture is not less than 10％, the delayed fracture strength ratio of a constant-load notch tension test is 0.63-0.71, no rare earth element is added, and the cost is low.
Inventors:
WANG LEI (CN)
ZHENG HONGWEI (CN)
LIU WENXUE (CN)
CHEN ZHAOYONG (CN)
ZHENG HONGWEI (CN)
LIU WENXUE (CN)
CHEN ZHAOYONG (CN)
Application Number:
PCT/CN2020/097868
Publication Date:
February 18, 2021
Filing Date:
June 24, 2020
Export Citation:
Assignee:
NANJING IRON & STEEL CO LTD (CN)
International Classes:
C21D9/00; C22C38/04; F16B35/00
Domestic Patent References:
| WO2007104117A1 | 2007-09-20 |
Foreign References:
| CN1900344A | 2007-01-24 | |||
| CN1900344A | 2007-01-24 | |||
| CN110468341A | 2019-11-19 | |||
| CN102597543A | 2012-07-18 | |||
| CN102876965A | 2013-01-16 | |||
| JP2019077911A | 2019-05-23 |
Attorney, Agent or Firm:
NANJING SUGAO PATENT AND TRADEMARK FIRM ( ORDINARY PARTNERSHIP ) (CN)
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