Analysis of Causes for Cracking of Chinese Large High-Strength Steel Spheric Tank and Suggestion About Its Prevention

2007 ◽  
Author(s):  
Xuedong Chen ◽  
Rong Yuan ◽  
Bing Wang ◽  
Tiecheng Yang ◽  
Pingjin Li ◽  
...  
Keyword(s):  
Failure Analysis ◽  
High Strength Steel ◽  
Field Survey ◽  
High Strength ◽  
Fabrication Process

In recent ten years, a number of cracking cases were reported on the in-service high-strength steel spheric tank made of 07MnCrMoVR and 07MnNiCrMoVDR steels (CF-62 steel for short) which were developed in China independently. Based on field survey, actual vessel inspection and failure analysis, it is pointed out that the quality of the steels, the problems existing in design and fabrication process and incompleteness of relevant standards are the major cause of cracking. Recommendations for cracking prevention of the high-strength steel spheric tank made of Chinese CF-62 steel are proposed.

Key Technology to Reduce Residual Stress Level of High Strength Steel

2012 ◽  
Vol 572 ◽  
pp. 221-226
Author(s):  
Wen Hong Ding
Keyword(s):  
Residual Stress ◽  
Stress Level ◽  
High Strength Steel ◽  
Rolling Force ◽  
Technical Problem ◽  
High Strength ◽  
Improve Performance ◽  
Key Technology ◽  
Servo Valve

Given that the traditional hot temper passing process cannot fulfill the demand of high strength steel on residual stress level and stable processability, leveler and temper passing process with dual servo valve (LTP-DSV) is developed to solve this technical problem. LTP-DSV process employs leveler to reduce residual stress level of high strength steel; uses dual servo valve variable gain rolling force control technology to improve performance stability of high strength steel; improves surface quality of high strength steel by means of temper passing. The residual stress level of products is substantially reduced on condition that the performance of high strength steel is ensured. The actual production data shows LTP-DS process is able to improve the performance and quality of high strength steel from all aspects.

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