CWA Calgary Fall Seminar 2014 Advancements in Special Alloy Welding

Transcription

1 CWA Calgary Fall Seminar 2014 Advancements in Special Alloy Welding Wednesday Nov. 19, 2014 Doors open at 11:30am, Lunch at 12 noon, Presentations to follow throughout the afternoon. This seminar is geared for all positions and technical aptitudes associated with welding and fabrication in Alberta. Location: Mustang Room BMO Centre, Calgary s Stampede Park Cost: $75 per person, includes lunch. Please RSVP to calgary@cwamembers.org by noon on Friday Nov. 14, We cannot guarantee your seat without a reservation. Presentations will include (1) Welding and Heat-Treating of Grade 91 Steel, (2) Shielding Gas Mixtures to Promote Low Diffusible Hydrogen Weld Deposits, (3) Welding and Strip Cladding of CrMo Alloys for Critical Applications in the Petrochemical Industry and (4) The Social Responsibility of Engineering Welds for Component Integrity Beyond Design Lifetimes. There will also be a brief update on the AWOC (Alberta Welder Optimization Committee) presented at this seminar. Page 1 of 5

2 Welding and Heat-Treating of Grade 91 Steel Leijun Li, PhD, University of Alberta Grade 91 steel, also known as modified 9Cr-1Mo, is a martensitic Cr-Mo steel that has been microalloyed with vanadium and niobium and has a controlled nitrogen content. The fabrication and use of Grade 91 steel in high temperature steam pressure vessels has become a subject of particular interest to the nuclear and fossil fuel power generation industries. This is because Grade 91 exhibits a superior level of creep strength and oxidation resistance at elevated temperatures. After welding, brittle martensite with unfavourable material properties is formed in the weld metal and heat-affected zone. Thus, heat treatment is required in order to produce tempered martensite with precipitated carbides and vanadium/niobium-rich carbo-nitrides that provide for acceptable material properties. We will discuss the phase transformations in welding and post-weld heat treatment, with a focus on the effect of post-weld heat treatment on the creep rupture properties of heavy section Grade 91 welds. Type IV rupture in the inter-critical heat-affected zone has been reproduced from the experiment welds made from flux-cored arc welding of Grade 91 piping and heavy section plates. In the range of 600 to 840C, 2 and 8-hour post-weld heat treatment, longer creep life is resulted from Grade 91 welds heat treated with a lower temperature and shorter time (600C, 2 hours). However, the room temperature toughness of the heat-affected zone only recovers after a 720 C, 2-hour post-weld heat treatment. Bio: Dr. Leijun Li is Professor of Physical Metallurgy and Welding with the Canadian Center for Welding and Joining (CCWJ) at University of Alberta. He has been an active member of the Welding Research Council (WRC) and American Welding Society (AWS) since 1994, serving on the Stainless and High Alloys, Technical Papers, Handbook, and Testing of Welds committees, and as Principal Reviewer for the Welding Journal and Key Reader for the Metallurgical and Materials Transactions. He is a past chair of the Joining Critical Technologies Committee of ASM International. Li received the Adams Memorial Award and W.H. Hobart Memorial Award from the AWS, and the Founders Award of Excellence from Rensselaer Polytechnic Institute, where he obtained his PhD from the W.F. Doc Savage Materials Joining Laboratory. He is a Fellow of ASM International. Page 2 of 5

3 Shielding Gas Mixtures to Promote Low Diffusible Hydrogen Weld Deposits W. F. Garth Stapon Business Development Manager Metal Fabrication, Praxair Weld metal hydrogen becomes a significant concern to fabricators as the strength of the materials used and the severity of the service conditions increases. Where fabricated flux- and metal-cored wires are used to join these materials, it is sometimes challenging and costly to produce the desired low hydrogen weld metal. The environmental conditions encountered during the use of these wire types, and the conditions under which these wires were stored prior to use and during use, can also have a significant influence on the final weld hydrogen content of a weld. Solid fluoride compounds are often incorporated into the core of flux-bearing wires in order to provide a source of fluorine to react with any hydrogen present in the arc environment. The intentional addition of a gaseous fluoride compound to the shielding gas provides additional capability to react with and remove hydrogen without interfering with the normal operating characteristic of the wire or negatively impacting the mechanical properties of the weld produced. It has been found that a small addition of a gaseous fluoride can significantly reduce weld hydrogen levels; reductions of approximately 50% have been achieved with a variety of flux-cored and metal-cored wire electrodes. It has also been demonstrated that wires that have been poorly stored and handled, such that they have absorbed moisture from the environment, can be successfully used with a fluoridecontaining shielding gas and again achieve lower weld hydrogen levels. The use of these fluoride-supplemented shielding gases in a variety of applications destined for use in arctic-like environments will be discussed in this presentation. Bio: During his more than 30 years in the welding industry, Garth Stapon has worked in shielding gas development (R&D) product management for consumables, and technical sales. He has been published on numerous occasions on shielding gas application technology. Garth graduated from Red River Community College in Winnipeg in 1980 as an apprentice welder. Today he is an AWS Certified Welding Supervisor and furthered his education at the Southern Alberta Institute of Technology in Calgary graduating in Garth recently returned to Canada following a multiyear work assignment at Praxair s Global Headquarters located in Danbury, CT. As a 16 year resident of CT, USA Garth and his family are proud to call Hamilton, Ontario their new home. Page 3 of 5

4 Welding and Strip Cladding of CrMo Alloys for Critical Applications in the Petrochemical Industry Russel Fuchs, Voestalpine Bohler Welding USA Design criteria for pressure equipment in the process industries place increasing demands on the materials of construction. Often times, specification requirements push the current materials of choice to the limit of their capabilities. Chromium-Molybdenum alloys are very popular in the petrochemical industry for the fabrication of pressure vessels that are designed to operate at elevated temperatures for extended periods of time. Welding of these materials can be a challenge since the typical specification requirements for the deposited weld metal call for controlled compositions to minimize the tendency for temper embrittlement, as well as good low temperature toughness properties of the initial fabrication to insure the integrity of the equipment over the design life. This presentation will discuss design considerations for the welding consumables as well as the proper application techniques required to successfully meet the most stringent requirements. In the past, there have not been any industry standards for the fabrication of these heavy wall pressure vessels and it was up to the individual owner companies to develop their own specifications. Recently, the American Petroleum Institute (API) has developed a set of recommended practices to standardize the requirements. This presentation will also include a discussion of the filler metal requirements according to the API RP 934 documents. Many applications call for the fabrication of pressure equipment that is resistant to corrosion at elevated temperatures. The most effective design would be to fabricate the component entirely from the corrosion resistant alloy (CRA). However, this is generally not economically feasible due to the thickness requirement of the pressure component and the high cost of the CRA. In most cases, it is more desirable to fabricate the pressure component from a stronger structural steel, and then apply the CRA to the surfaces that require protection. The corrosion resistant layer can be applied by several different methods, with weld cladding being one of the more popular. When weld cladding, various processes can be used, with each process having advantages depending upon the application criteria. When large surface areas require cladding, using the strip cladding process is often times the best solution. This presentation will discuss the fundamentals of the strip cladding process, comparing conventional submerged arc to electroslag. Also discussed will be recent developments to improve productivity and economics, as well as a review of various applications. Bio: Russel Fuchs is currently the Manager of Technology and Industry Segments for voestalpine Bohler Welding USA, located in Houston, Texas. His primary responsibility is technical support of the sales activities of the Company in the United States and Canada. Russel has been with voestalpine Bohler Welding for 29 years. Page 4 of 5

5 Previous to voestalpine Bohler Welding USA, Russel spent 6 years with a major engineering and construction company as a Welding Engineer. He has a Bachelor of Science degree from Texas A&M University, with a specialization in Welding Metallurgy. Russel is a life member of the American Welding Society and serves on the AWS A5 Committee on Filler Metals and Allied Materials, along with the A5D subcommittee for Stainless Steels and as chairman of the A5E subcommittee for Nickel Base alloys. He is also active with several industry code bodies and organizations, such as ASME, API, and NACE. The Social Responsibility of Engineering Welds for Component Integrity Beyond Design Lifetimes Stuart Guest, PhD., EIT Integrity Specialist (Welding) - Materials, Welding, & Inspection Stantec Pressure equipment and pipeline industries are under the microscope and must strive for zero leaks and zero accidents to satisfy the public, regulators, partners, and peers. This global movement places additional pressures on consultants, suppliers, and fabricators to deliver on time, at the highest quality, and under budget. Welding threatens zero leak policies as there is a higher likelihood of deleterious defects or unintentional workmanship errors that decrease the component integrity. This seminar will focus on factors that affect weld integrity and how they can be controlled. Vintage and modern materials will be discussed with reference to designing a robust and engineered weld procedure that is resistant to welder and material inconsistencies. This will evolve into cooling curve analysis to approximate the ideal set of welding parameters. Parallel to robust weld procedure development, the seminar will delve deeper into weld joint design for strain-based designs with modern materials and processes. The effect of weld defect sizes and types will be discussed with a focus on the social responsibilities of fabricating and operating components to a zero leak policy. Examples of the discussion topics will be provided throughout the seminar to connect theory to reality. Bio: Stuart is the Welding Program Leader for Stantec s Oil and Gas division and holds a PhD. in Welding Engineering from the Canadian Centre for Welding and Joining. He has 4 years of experience in welding process design, advanced materials for oil sands applications, modern pipeline materials, robust WPS design, in-service pipeline repair weld procedure development, WPS review, gap analysis and procedure planning, R&D and project management, and weld overlays. He has a passion for the strategic implementation of new technologies to drive welding and manufacturing forward in Alberta and Canada. He maintains close working ties with many individuals involved in welding research. Page 5 of 5