Fracture of alloy steels by intergranular microvoid coalescence as influenced by composition and heat treatment

1973 ◽  
Vol 4 (10) ◽  
pp. 2485-2489 ◽  
Author(s):  
B. J. Schulz ◽  
C. J. McMahon
Keyword(s):  
Heat Treatment ◽  
Microvoid Coalescence ◽  
Alloy Steels

Study of Hydrogen Cracking and PWHT of Dissimilar Materials for Elevated Temperature Application

2015 ◽  
Vol 754-755 ◽  
pp. 797-801
Author(s):  
Muhammad Sarwar ◽  
Mohd Amin bin Abd Majid
Keyword(s):  
Heat Treatment ◽  
Dissimilar Materials ◽  
High Hardness ◽  
Construction Sites ◽  
Gas Tungsten Arc ◽  
Martensitic Microstructure ◽  
Alloy Steels ◽  
Temperature Application ◽  
The Impact ◽  
Hardness Values

s. On construction sites many challenges and premature failures are being encountered in welded joints of creep strength-enhanced ferritic (CSEF) steels. The primary reason of these premature failures is found to be the dissimilar material joints, having strength mismatch, or improper heat treatment that is mandatorily carried out to achieve the required weld hardness. This study aims at determining the impact of post welding heat treatment (PWHT) on dissimilar alloy steels joints, between ASTM A335 Gr. P-22 and ASTM A335 Gr. P-91 steels, welded by gas tungsten arc welding (GTAW) using ER 90S-B9 filler wire. The PWHT, at 745°C for 1hr., was applied to attain the required hardness. The effect of PWHT was investigated on the weld metal and the heat affected zones (HAZ) by hardness testing. Due to the martensitic microstructure, the hardness values of HAZ of P91 steel are over 350 HV. However, the hardness value of the P22 HAZ less than 350 HV. P91 HAZ has a higher hardness value than P22 HAZ because of its higher hardenability and due to phase transformation from martensite to ferrite. The interaction between the too high hardness microstructure with hydrogen can result in the hydrogen induced cracking (HIC) initiation in the HAZ. Therefore, the PWHT is needed to reduce this high hardness HAZ.

The Influence of Austenisation Temperature and Holding Time on Mechanical Properties, Scale Thickness, and Microstructure in Alloy Steel

2015 ◽  
Vol 776 ◽  
pp. 239-245
Author(s):  
Abdul Aziz ◽  
Maulud Hidayat ◽  
Indah Hardiyanti
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Alloy Steel ◽  
Impact Energy ◽  
Holding Time ◽  
Micro Structure ◽  
Scale Thickness ◽  
Alloy Steels ◽  
Steel Weight

The application of steel products have been widely used and various research have been developed to find a good and appropriate quality of steel and can be produced in the country without have to be imported, for example alloy steels. One of the alloy steels that have been constantly developed is Ni-Cr-Mo alloy steel with additional nickel, chromium and molybdenum which can increase hardness, tensile strength, ductility and toughness. The effect during the production process is at the heating process that causes the formation of iron oxide layer (scale) and the loss of steel weight. Therefore, the selection of heat treatment methods and techniques are required to increase the mechanical properties of steel, such as hardness, tensile strength, and toughness, with the scale is about <5% of steel weight. In this research, the heat treatment was carried out at austenisation temperature of 800°, 850°, 900°C and at holding time of 20, 40, 60 minutes, then followed by a rapid cooling (quenching) to improve the mechanical properties of hardness. This research also tested the mechanical properties of steel that consist of hardness test and impact test, and metallographic observation that consist of micro structure observation and scale thickness observation. The micro structure from heat treatment process is martensite, it is due to a rapid cooling (quenching) that rapidly change the austenite phase into martensite. The data showed the highest hardness is 588.35 HVN at 850°C of temperature and 60 minutes of holding time, 8.5 Joules of impact energy, and 91.5 μm of scale thickness. While the lowest hardness is 539.34 HVN at 800°C of temperature, 5 Joules of impact energy, and 47.81 μm of scale thickness.

scholarly journals Effect of tempering heat treatment on the CO2 corrosion resistance of quench-hardened Cr-Mo low-alloy steels for oil and gas applications

2019 ◽  
Vol 154 ◽  
pp. 36-48 ◽  
Author(s):  
Clara. Escrivà-Cerdán ◽  
Steve W. Ooi ◽  
Gaurav R. Joshi ◽  
Roberto Morana ◽  
H.K.D.H. Bhadeshia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Oil And Gas ◽  
Co2 Corrosion ◽  
Low Alloy Steels ◽  
Alloy Steels

Aspects of thermal transfer in heat treatment of alloy steels using concentrated solar energy

2019 ◽  
Vol 138 (4) ◽  
pp. 2541-2553
Author(s):  
Dorin Catana ◽  
Jose Rodriguez ◽  
Inmaculada Cañadas ◽  
Ioan Milosan
Keyword(s):  
Heat Treatment ◽  
Solar Energy ◽  
Thermal Transfer ◽  
Concentrated Solar Energy ◽  
Alloy Steels

Alternative Approach for Qualification of Temperbead Welding in the Nuclear Industry

2012 ◽  
Author(s):  
Steven L. McCracken ◽  
Richard E. Smith
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Alloy Steel ◽  
Nuclear Power ◽  
Post Weld Heat Treatment ◽  
Nuclear Power Industry ◽  
Low Alloy Steels ◽  
Low Alloy Steel ◽  
Alloy Steels ◽  
Weld Heat

Temperbead welding is common practice in the nuclear power industry for in-situ repair of quenched and tempered low alloy steels where post weld heat treatment is impractical. The temperbead process controls the heat input such that the weld heat-affected-zone (HAZ) in the low alloy steel is tempered by the welding heat of subsequent layers. This tempering eliminates the need for post weld heat treatment (PWHT). Unfortunately, repair organizations in the nuclear power industry are experiencing difficulty when attempting to qualify temperbead welding procedures on new quenched and tempered low alloy steel base materials manufactured to modern melting and deoxidation practices. The current ASME Code methodology and protocol for verification of adequate fracture toughness in materials was developed in the early 1970s. This paper reviews typical temperbead qualification results for vintage heats of quenched and tempered low alloy steels and compares them to similar test results obtained with modern materials of the same specification exhibiting superior fracture toughness.

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