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.

Review of Pressure Vessel Code Rules on Cold Forming Limits and Heat Treatment Requirements

2019 ◽  
Author(s):  
Kang Xu ◽  
Mahendra D. Rana ◽  
James White
Keyword(s):  
Experimental Data ◽  
Heat Treatment ◽  
Pressure Vessel ◽  
Service Condition ◽  
Forming Limits ◽  
Cold Forming ◽  
Alloy Steels ◽  
Section Viii ◽  
Technical Basis ◽  
The Impact

Abstract In pressure vessel fabrication, cold formed carbon and alloy steels are required to have a subsequent heat treatment because of the loss of ductility and toughness from cold forming. The requirements for heat treatment are dependent on the materials, thickness, amount of cold forming and service condition. There are significant differences among the pressure vessel codes on the requirements for cold forming heat treatment. In this paper, the code requirements for cold forming heat treatment are reviewed for ASME Section VIII Divisions 1 and 2, EN 13445-4 and GB-150. The technical basis of forming strain calculations is discussed. Based on experimental data on the impact toughness as a function of forming strain, and fracture mechanics studies on cold formed components, improved guidelines are proposed on cold forming limits for heat treatment.

Study of Weld Hardness of Pipes at Elevated Temperature Application in Power Plants

2014 ◽  
Vol 1025-1026 ◽  
pp. 310-316
Author(s):  
Muhammad Sarwar ◽  
Mohd Amin bin Abd Majid
Keyword(s):  
Elevated Temperature ◽  
Creep Strength ◽  
Power Plants ◽  
Welding Current ◽  
Travel Speed ◽  
Construction Sites ◽  
Gas Tungsten Arc ◽  
Close Relationship ◽  
Temperature Application

Weld hardness has close relationship with creep strength and ductility of the welded structures. Hence it is important for any weld to achieve certain level of weld hardness. This study aims at identifying the parameters that affect the quality of weld in achieving the required weld quality in terms of hardness and to establish the relationship between different factors that affect the weld hardness. The focus is to study and explore the welding input parameters for the gas tungsten arc welding (GTAW) of elevated temperature piping used in power plants and to predict the weld hardness on construction sites. The Design of Experiment (DoE) is used in analyzing the related parameters. The data generated through experiments has been validated for the hardness based on input process parameters (welding current, welding voltage, travel speed, welding rod diameter). The findings from the study revealed that the most important factor influencing the hardness of creep-strength enhanced ferritic (CSEF) material welds is the voltage while other factors have minimum or the least influence for the studied ranges and factors.

scholarly journals Tribological Properties on P91 Alloy Steel Treated with Normalizing & Carburizing Process

2019 ◽  
Vol 9 (1) ◽  
pp. 2078-2082 ◽  
Keyword(s):  
Heat Treatment ◽  
Wear Test ◽  
High Hardness ◽  
Hardness Test ◽  
Variable Load ◽  
X Ray Diffraction ◽  
P91 Steel ◽  
Treatment Processes ◽  
Pin On Disc ◽  
Alloy Steels

An Experimental analysis was undertaken to analyze the changes in the Mechanical Properties and Microstructure of P91 steel, subjected to Normalizing and Carburizing heat treatment Processes keeping in mind the potential capabilities of P91 steel as the base metal due to its wide applications in Boilers manufacturing. P91 is a type of alloy steels having high hardness and wear resistance suface. The heat treatment processes were carried out in the present experimental procedure at constant temperature and for different timings like 60 minutes, 90 minutes and 120 minutes. Hardness of the specimen was tested by using Rockwell Hardness test. A pin on disc machine was used to conduct the wear test. Wear test was carried out on treated P91 steel on various parameters like variable load and constant speed. The Microstructural results are concluded with SEM (Scanning Electron Microscope) and XRD (X-Ray diffraction) techniques

scholarly journals Effect of Different Variants of Heat Treatment on Mechanical Properties of the AlSi17CuNiMg Alloy

2016 ◽  
Vol 16 (2) ◽  
pp. 41-44 ◽  
Author(s):  
A. Jarco ◽  
J. Pezda
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Impact Strength ◽  
High Hardness ◽  
Dispersion Hardening ◽  
Initial State ◽  
Plastic Properties ◽  
Fourfold Increase ◽  
The Impact

Abstract Dispersion hardening, as the main heat treatment of silumins having additions of copper and magnesium, results in considerable increase of tensile strength and hardness, with simultaneous decrease of ductility of the alloy. In the paper is presented an attempt of introduction of heat treatment operation consisting in homogenizing treatment prior operation of the dispersion hardening, to minimize negative effects of the T6 heat treatment on plastic properties of hypereutectoidal AlSi17CuNiMg alloy. Tests of the mechanical properties were performed on a test pieces poured in standardized metal moulds. Parameters of different variants of the heat treatment, i.e. temperature and time of soaking for individual operations were selected basing on the ATD (Thermal Derivation Analysis) diagram and analysis of literature. The homogenizing treatment significantly improves ductility of the alloy, resulting in a threefold increase of the elongation and more than fourfold increase of the impact strength in comparison with initial state of the alloy. Moreover, the hardness and the tensile strength (Rm) of the alloy decrease considerably. On the other hand, combination of the homogenizing and dispersion hardening enables increase of elongation with about 40%, and increase of the impact strength with about 25%, comparing with these values after the T6 treatment, maintaining high hardness and slight increase of the tensile strength, comparing with the alloy after the dispersion hardening.

scholarly journals Cryogenic Hardening of EN 19 Alloy Steel

2019 ◽  
Vol 8 (10) ◽  
pp. 158-161
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Treatment Process ◽  
Cryogenic Treatment ◽  
Heat Treatment Process ◽  
Wear Protection ◽  
Hardening Process ◽  
Alloy Steels ◽  
Increase Wear Resistance ◽  
The Impact

This paper includes the study of heat treatment process that we carried out on En 19 steel in cryogenic atmosphere. Cryogenic treatments of alloy steels have been significantly increase wear resistance and toughness. These investigations of warmth treatment cryogenic medicines of amalgam steels have been asserted to altogether expand wear protection and sturdiness. Cryogenic handling is a supplementary procedure to customary warmth treatment process in steels. The cryogenic treatment on apparatus materials builds the life of instruments, gear, parts and materials by boosting elasticity, sturdiness and strength. This cryogenic hardening process is an onetime treatment influencing the whole part — not only the surface. Cryogenic treatment has been broadly embraced as a cost decrease and execution upgrading innovation. Cryogenic treatment is likewise utilized as an empowering innovation, when its pressure alleviating benefits are used to allow the manufacture (or machining) of basic resistance parts. With regards to great outcomes about the use of profound cryogenic treatment (DCT) on materials, the impact on the microstructure and properties (hardness, strength and the substance of held austenite) are observed to be made strides. Cryogenic treatment has been distinguished to improve the properties of Tools steels. It is discovered that cryogenic treatment confers almost 110% change in apparatus life.

Why Nitride?

2003 ◽  
pp. 13-22
Keyword(s):  
Wear Resistance ◽  
High Surface ◽  
High Hardness ◽  
Abrasive Wear Resistance ◽  
High Wear Resistance ◽  
Minimal Distortion ◽  
Resistance To Oxidation ◽  
Alloy Steels ◽  
High Torque ◽  
Hardness Values

Abstract The unique advantages of the nitriding process were recognized by the Germans in the early 1920s. It was used in applications that required: high torque, high wear resistance; abrasive wear resistance; corrosion resistance; and high surface compressive strength. This chapter focuses on key process considerations and factors that helped nitriding gain acceptance. These include a low-temperature process, no quench requirement, minimal distortion, high hardness values, resistance to oxidation, and the core properties of nitrided alloy steels.

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

ALMANITE W

Alloy Digest ◽  
1974 ◽  
Vol 23 (3) ◽  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Surface Treatment ◽  
High Hardness ◽  
Heat Treating ◽  
Austenitic Matrix ◽  
Matrix Type ◽  
Martensitic Matrix ◽  
Cast Condition

Abstract ALMANITE W comprises a series of three types of austenitic-martensitic white irons characterized by high hardness and relatively good impact strength. Type W1 has a pearlitic matrix. Type W2 has a martensitic matrix, Type W4 is highly alloyed to provide an austenitic matrix in the as-cast condition which may be further modified to give a martensitic matrix by heat treatment or by refrigeration. This datasheet provides information on composition, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-42. Producer or source: Meehanite Metal Corporation.

CPM REX 25

Alloy Digest ◽  
1980 ◽  
Vol 29 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
High Speed Steel ◽  
High Hardness ◽  
Heat Treating ◽  
High Speeds ◽  
Aisi Type ◽  
Tool Performance ◽  
End Mills ◽  
Machining Operations

Abstract CPM REX 25 is a super high-speed steel made without cobalt. It is comparable to AISI Type T15 cobalt-containing high-speed steel in response to heat treatment, properties, and tool performance. CPM REX 25 is recommended for machining operations requiring heavy cuts, high speeds and feeds, and difficult-to-machine materials of high hardness and abrasion resistance. Typical applications are boring tools, drills, gear cutters, punches, form tools, end mills and broaches. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-365. Producer or source: Crucible Materials Corporation.

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