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.

Heat Treatment of Fabricated Components and the Effect on Properties of Materials

2019 ◽  
Author(s):  
Shyam Gopalakrishnan ◽  
Ameya Mathkar
Keyword(s):  
Heat Treatment ◽  
Pressure Vessel ◽  
Test Specimen ◽  
Stress Relieving ◽  
Division 1 ◽  
Asme Code ◽  
Alloy Steels ◽  
Section Viii ◽  
Properties Of Materials ◽  
Division 2

Abstract Most of the heavy thickness boiler and pressure vessel components require heat treatment — in the form of post weld heat treatment (PWHT) and sometimes coupled with local PWHT. It is also a common practice to apply post heating/ intermediate stress relieving/ dehydrogenation heat treatment in case of alloy steels. The heat treatment applied during the various manufacturing stages of boiler and pressure vessel have varying effects on the type of material that is used in fabrication. It is essential to understand the effect of time and temperature on the properties (like tensile and yield strength/ impact/ hardness, etc.) of the materials that are used for fabrication. Considering the temperature gradients involved during the welding operation a thorough understanding of the time-temperature effect is essential. Heat treatments are generally done at varying time and temperatures depending on the governing thickness and the type of materials. The structural effects on the materials or the properties of the materials tends to vary based on the heat treatment. All boiler and pressure vessel Code require that the properties of the material should be intact and meet the minimum Code specification requirements after all the heat treatment operations are completed. ASME Code(s) like Sec I, Section VIII Division 1 and Division 2 and API recommended practices like API 934 calls for simulation heat treatment of test specimen of the material used in fabrication to ascertain whether the intended material used in construction meets the required properties after all heat treatment operations are completed. The work reported in this paper — “Heat treatment of fabricated components and the effect on properties of materials” is an attempt to review the heat treatment and the effect on the properties of materials that are commonly used in construction of boiler and pressure vessel. For this study, simulation heat treatment for PWHT of test specimen for CS/ LAS plate and forging material was carried out as specified in ASME Section VIII Div 1, Div 2 and API 934-C. The results of heat treatment on material properties are plotted and compared. In conclusion recommendations are made which purchaser/ manufacturer may consider for simulation heat treatment of test specimen.

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.

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.

Intensive Quenching Theory and Application for Imparting High Residual Surface Compressive Stresses in Pressure Vessel Components

2003 ◽  
Vol 125 (2) ◽  
pp. 188-194 ◽  
Author(s):  
Andrew M. Freborg ◽  
B. Lynn Ferguson ◽  
Michael A. Aronov ◽  
Nikolai I. Kobasko ◽  
Joseph A. Powell
Keyword(s):  
Heat Treatment ◽  
Pressure Vessel ◽  
Cost Effective ◽  
Heat Treating ◽  
Environmental Benefits ◽  
Plain Water ◽  
Treatment Practices ◽  
Compressive Stresses ◽  
Part Surface ◽  
Alloy Steels

An alternative method for the hardening of steel parts has been developed as a means of providing steel products with superior mechanical properties through development of high residual compressive stresses on the part surface, and involves the application of intensive quenching during heat treatment. This processing method, termed “Intensive Quenching,” imparts high residual compressive stresses on the steel surface, thus allowing for the use of lower alloy steels, reduction or elimination of the need for carburization and shot peening, and providing for more cost-effective heat treating. Intensive quenching also provides additional environmental benefits, as the process uses plain water as the quenching media in contrast to traditional heat treatment practices which typically employ hazardous and environmentally unfriendly quenching oil. This paper presents an overview of the theory and application of intensive quenching, as well as provides experimental and computational data obtained for a variety of steel products. Also presented will be results of computer simulations of temperature, structural and stress/strain conditions for a typical pressure vessel during intensive quenching.

Technical Basis of Material Toughness Requirements in the ASME Boiler and Pressure Vessel Code, Section VIII, Division 2

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
David A. Osage ◽  
Martin Prager
Keyword(s):  
Impact Test ◽  
Major Change ◽  
Low Alloy Steels ◽  
Beneficial Effects ◽  
Division 1 ◽  
Alloy Steels ◽  
Section Viii ◽  
Assessment Procedures ◽  
Technical Basis ◽  
Division 2

The development of new toughness requirements for carbon and low alloy steels was a major part of the effort to rewrite the ASME B&PV Code, Section VIII, Division 2. The new toughness rules in this code were established using the fracture mechanics assessment procedures in API 579-1/ASME FFS-1 (Fitness-For-Service), Part 9. The major change in the toughness rules when compared to older editions of Section VIII, Division 2 (2004 and prior) and the current edition of Section VIII, Division 1 are for carbon and low alloy steel materials excluding bolting. The new toughness rules in Section VIII, Division 2 are based on a Charpy V-Notch impact requirement of 20 ft-lb (27 J) consistent with European practice and the beneficial effects of post weld heat treatment are included consistent with the procedures in API 579-1/ASME FFS-1. This paper provides a technical background to the new toughness rules including the development of material toughness requirements and the development of impact test exemption rules.

scholarly journals NIOBIUM ALLOY STEEL APPLIED IN COLD FORMING MANUFACTURE

2019 ◽  
Vol 27 (27) ◽  
pp. 23-29
Author(s):  
Bruno Inácio MAIA ◽  
André Hideto FUTAMI ◽  
Marco Aurélio DE OLIVEIRA ◽  
Luiz Veriano Oliveira DALLA VALENTINA
Keyword(s):  
Heat Treatment ◽  
Mechanical Performance ◽  
Niobium Alloy ◽  
Performance Comparison ◽  
Forming Process ◽  
Cold Forming ◽  
Positive Performance ◽  
Alloy Steels ◽  
Reducing Costs ◽  
Metallurgy Industry

Niobium alloy steels are still little known and debated when applied to the metallurgy industry, including cold forming process. It is not much clear about its characteristics and your mechanical performance when compared to traditional steels, which the market already uses. The possibility of input new materials, reducing costs and generating competitiveness is the basis for researches that can generate new opportunities for industries. In this article, we showed the possibility of withdrawing the heat treatment process, which guided the execution of the tests presented here. This paper deals with the performance comparison of SAE 1312 MOD steel compared to ISO 898-1, which deals with mechanical performance for bolts. The tests were correlated with the bolts of 8.8 resistance class, which currently have heat treatment. It is possible to evaluate the positive performance of the niobium-alloyed steel (SAE 1312 MOD), despite the occasional performance limitations in some attributes addressed in ISO 898-1.

Intensive Quenching Theory and Application for Imparting High Residual Surface Compressive Stresses in Pressure Vessel Components

2002 ◽  
Author(s):  
Michael A. Aronov ◽  
Nikolai I. Kobasko ◽  
Joseph A. Powell ◽  
Andrew M. Freborg ◽  
B. Lynn Ferguson
Keyword(s):  
Heat Treatment ◽  
Pressure Vessel ◽  
Cost Effective ◽  
Heat Treating ◽  
Environmental Benefits ◽  
Plain Water ◽  
Treatment Practices ◽  
Compressive Stresses ◽  
Part Surface ◽  
Alloy Steels

An alternative method for the hardening of steel parts has been developed as a means of providing steel products with superior mechanical properties through development of high residual compressive stresses on the part surface, and involves the application of intensive quenching during heat treatment. This processing method, commercially patented under the name IntensiQuench SM, imparts high residual compressive stresses on the steel surface, thus allowing for the use of lower alloy steels, reduction or elimination of the need for carburization and shot peening, and providing for more cost-effective heat treating. Intensive quenching also provides additional environmental benefits, as the process uses plain water as the quenching media in contrast to traditional heat treatment practices which typically employ hazardous and environmentally unfriendly quenching oil. This paper presents an overview of the theory and application of intensive quenching, as well as provides experimental and computational data obtained for a variety of steel products. Also presented will be results of computer simulations of temperature, structural and stress/strain conditions for a typical pressure vessel during intensive quenching.

scholarly journals Niobium alloy steel applied in cold forming manufacture

2019 ◽  
pp. 23-29
Author(s):  
Bruno Inácio Maia ◽  
André Hideto Futami ◽  
Marco Aurélio De Oliveira ◽  
Luiz Veriano Oliveira Valentina
Keyword(s):  
Heat Treatment ◽  
Mechanical Performance ◽  
Niobium Alloy ◽  
Performance Comparison ◽  
Forming Process ◽  
Cold Forming ◽  
Positive Performance ◽  
Alloy Steels ◽  
Reducing Costs ◽  
Metallurgy Industry

Niobium alloy steels are still little known and debated when applied to the metallurgy industry, including cold forming process. It is not much clear about its characteristics and your mechanical performance when compared to traditional steels, which the market already uses. The possibility of input new materials, reducing costs and generating competitiveness is the basis for researches that can generate new opportunities for industries. In this article, we showed the possibility of withdrawing the heat treatment process, which guided the execution of the tests presented here. This paper deals with the performance comparison of SAE 1312 MOD steel compared to ISO 898-1, which deals with mechanical performance for bolts. The tests were correlated with the bolts of 8.8 resistance class, which currently have heat treatment. It is possible to evaluate the positive performance of the niobium-alloyed steel (SAE 1312 MOD), despite the occasional performance limitations in some attributes addressed in ISO 898-1.

The Technical Basis of the External Pressure Section of BS5500

1984 ◽  
Vol 106 (2) ◽  
pp. 143-149 ◽  
Author(s):  
S. Kendrick
Keyword(s):  
Pressure Vessel ◽  
External Pressure ◽  
Section Viii ◽  
Dome Collapse ◽  
Technical Basis

The technical basis of the external pressure section of the British Pressure Vessel Code BS5500 is presented. Interstiffener collapse of cylinders, overall collapse, sideways tripping of stiffeners and dome collapse are all considered. Some comparisons are given with the equivalent American Code ASME Section VIII.

Impact Toughness and Brittle Failure of Carbon Steels

2017 ◽  
Author(s):  
Kang Xu ◽  
Mahendra Rana
Keyword(s):  
Fracture Mechanics ◽  
Impact Toughness ◽  
Pressure Vessel ◽  
Brittle Failure ◽  
Carbon Steels ◽  
Root Cause ◽  
Section Viii ◽  
Mechanics Concepts ◽  
High Level ◽  
The Impact

Brittle failure of pressure containing equipment can lead to catastrophic consequences and must be prevented. ASME pressure vessel codes have developed clear rules on toughness requirements based on both long term safe and reliable experience and fracture mechanics concepts. The essence of the toughness rules in ASME Boiler and Pressure Vessel (B&PV) Codes Section VIII, Division 1 and Division 2 is a set of impact test exemptions curves and impact toughness requirements as a function of materials’ yield strength and thickness. Considering the limitations of the impact toughness in characterizing the resistance to brittle fracture, a high level of conservatism is built into the toughness rules. It should be emphasized that impact tests are satisfactory as a rule making tool for quality control, but impact toughness values by themselves cannot be reliably used to predict materials’ resistance to brittle failure. Fracture mechanics analysis should be performed to investigate the root cause of a brittle failure, instead of relying solely on impact toughness values.

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