Determination of the crack resistance of low-alloy steels for main pipelines

1987 ◽  
Vol 23 (2) ◽  
pp. 177-181 ◽  
Author(s):  
P. D. Odesskii ◽  
V. A. Ratov ◽  
O. N. Vinkler
Keyword(s):  
Crack Resistance ◽  
Low Alloy Steels ◽  
Main Pipelines ◽  
Alloy Steels

Design, Manufacture and Safety Aspects of Forged Vessels for High-Pressure Services

1980 ◽  
Vol 102 (1) ◽  
pp. 98-106 ◽  
Author(s):  
G. J. Mraz ◽  
E. G. Nisbett
Keyword(s):  
High Pressure ◽  
Pressure Vessel ◽  
Low Alloy Steels ◽  
Nickel Chromium ◽  
Molybdenum Alloys ◽  
Tension Tests ◽  
Alloy Steels ◽  
Section Viii ◽  
Division 2

Steels at present included in Sections III and VIII of the ASME Boiler and Pressure Vessel Code severely limit its application for high-pressure design. An extension of the well-known AISI 4300 series low alloy steels has long been known as “Gun Steel.” These alloys, which are generally superior to AISI 4340, offer good harden-ability and toughness and have been widely used under proprietary names for pressure vessel application. The ASTM Specification A-723 was developed to cover these nickel-chromium-molybdenum alloys for pressure vessel use, and is being adopted by Section II of the ASME Boiler and Pressure Vessel Code for use in Section VIII, Division 2, and in Section III in Part NF for component supports. The rationale of the specification is discussed, and examples of the mechanical properties obtained from forgings manufactured to the specification are given. These include the results of both room and elevated temperature tension tests and Charpy V notch impact tests. New areas of applicability of the Code to forged vessels for high-pressure service using these materials are discussed. Problems of safety in operation of monobloc vessels are mentioned. Procedures for in-service inspection and determination of inspection intervals based on fracture mechanics are suggested.

The Determination of Carbide Types in Thin-Film Specimens of Low Alloy Steels.

2000 ◽  
Vol 6 (S2) ◽  
pp. 348-349 ◽  
Author(s):  
A.J. Papworth ◽  
M. Watanabe ◽  
D.B. Williams
Keyword(s):  
Auger Electron ◽  
Temper Embrittlement ◽  
Thermal Exposure ◽  
Low Alloy Steels ◽  
Austenite Grain ◽  
Alloy Steels ◽  
Electron Spectrometry ◽  
Prior Austenite Grain

The introduction of “clean steels” was thought to have cured the problem of temper embrittlement in low alloy steels. However, even these steels exhibit temper embrittlement at services temperature above 400°C. Initial studies of temper embrittlement of clean steels used Auger electron spectrometry of fracture surfaces. The failure was found to occur along the prior austenite grain boundaries (PAGBs) where P segregation was found. It has been reported that the concentration of segregants changes along individual PAGB facets, as well as between the facets of different PAGBs. It was proposed that different elements segregate to different PAGBs, depending on their orientation. Differences in segregation along individual PAGBs were attributed to precipitation during thermal exposure, as identified by AEM. The cause of temper embrittlement is still unknown, as there are doubts about the role of precipitation. This implies that each PAGB may have a different chemistry.

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