Hot Isostatic Pressing of Large Bore, Stainless Steel Pipework for a Safety Critical Application

2011 ◽  
Vol 378-379 ◽  
pp. 752-758
Author(s):  
John L. Sulley ◽  
Brian K. Bull ◽  
Andrew C. Wood
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nuclear Reactor ◽  
Hot Isostatic Pressing ◽  
Straight Pipe ◽  
Reactor Plant ◽  
Isostatic Pressing ◽  
Safety Critical ◽  
Safety Critical Application ◽  
Product Forms

This paper presents an overview of the work undertaken by Rolls-Royce to introduce Hot Isostatically Pressed (HIP) large bore, austenitic stainless steel pipework into a safety critical application - a Nuclear Reactor plant. It describes the advantages of using HIP product forms to combine separate sections of straight pipe and elbows and, in so doing, reducing the number of structural plant welds.

scholarly journals Microstructure, Mechanical, and Corrosion Properties of Ni-Free Austenitic Stainless Steel Prepared by Mechanical Alloying and HIPping

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3416
Author(s):  
Eliza Romanczuk ◽  
Krzysztof Perkowski ◽  
Zbigniew Oksiuta
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Total Elongation ◽  
Nitrogen Atmosphere ◽  
Corrosion Properties ◽  
Isostatic Pressing

An influence of the powder metallurgy route on the phase structure, mechanical properties, and corrosion resistance of Fe–18%Cr–12%Mn–N nickel-free austenitic stainless steel as a potential material for medical applications were studied. The powder was mechanically alloyed in a high purity nitrogen atmosphere for 90 h followed by Hot Isostatic Pressing at 1150 °C (1423 K) and heat treatment at 1175 °C (1423 K) for 1 h in a vacuum with furnace cooling and water quenching. More than 96% of theoretical density was obtained for the samples after Hot Isostatic Pressing that had a direct influence on the tensile strength of the tested samples (Ultimate Tensile Strength is 935 MPa) with the total elongation of 0.5%. Heat treatment did not affect the tensile strength of the tested material, however, an elongation was improved by up to 3.5%. Corrosion properties of the tested austenitic stainless steel in various stages of the manufacturing process were evaluated applying the anodic polarization measurements and compared with the austenitic 316LV stainless steel. In general, the heat treatment applied after Hot Isostatic Pressing improved the corrosion resistance. The Hot Isostatic Pressing sample shows dissolution, while heat treatment causes a passivity range, the noblest corrosion potential, and lower current density of this sample.

Hot Isostatic Pressing of Austenitic Stainless Steel Powders for Pressure Retaining Applications

2004 ◽  
Author(s):  
W. Barry Burdett ◽  
Paul Hurrell ◽  
Alan Gilleland
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Structural Integrity ◽  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Nuclear Industry ◽  
Metal Powders ◽  
Isostatic Pressing ◽  
Wide Range

Hot Isostatic Pressing (HIP) has been used for many years to consolidate porosity in cast metal shapes to improve mechanical properties. When the technique is applied to fine metal powders, it becomes possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties and reduced cost. Manufacture of NNS items from powder delivers cost savings by reducing initial material usage and subsequent machining costs. Powder production and HIP processing are automated methods, which also provide protection against forging route obsolescence. Setup costs are lower and smaller batch sizes possible. HIPped powder microstructures are isotropic and equi-axed, with uniformly fine grain sizes not normally achieved in heavy section components. In austenitic stainless steel materials, this provides significant improvements in ultrasonic NDE (Non-Destructive Examination) in thick sections. Use of the technology has grown, particularly in the off-shore oil industry where it is already established in high integrity applications, but take-up in the more conservative nuclear industry has been slow. In a broad programme of testing, Rolls-Royce has established that HIPped powder 316L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion properties across a wide range of test environments. A methodology for developing robust safety justifications for use has been developed. Manufacture of pressure seal components is now in progress and the economics of other applications such as pump bowls are being considered. The quality of HIPped powder items can provide through life cost savings since there is greater assurance of structural integrity compared to welded or wrought components.

scholarly journals Study on the Hot Deformation Characterization of Borated Stainless Steel by Hot Isostatic Pressing

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7110
Author(s):  
Yanbin Pei ◽  
Xuanhui Qu ◽  
Qilu Ge ◽  
Tiejun Wang
Keyword(s):  
Stainless Steel ◽  
Hot Deformation ◽  
True Strain ◽  
Hot Isostatic Pressing ◽  
Microstructural Analysis ◽  
Critical Conditions ◽  
True Strain Rate ◽  
Isostatic Pressing ◽  
Different Temperatures ◽  
Borated Stainless Steel

Borated stainless steel (BSS) specimens have a boron content of 1.86 wt%, and are prepared by hot isostatic pressing (HIP) conducted at different temperatures, ranging from 1000 to 1100 °C and a constant true strain rate (0.01, 0.1, 1 and 10 s−1). These tests, with observations and microstructural analysis, have achieved the hot deformation characteristics and mechanisms of BSS. In this research, the activation energy (Q) and Zener–Hollomon parameter (Z) were contrasted against the flow curves: Q = 442.35 kJ/mol. The critical conditions associated with the initiation of dynamic recrystallization (DRX) for BSS were precisely calculated based on the function between the strain hardening rate with the flow stress: at different temperatures from 1000 to 1100 °C: the critical stresses were 146.69–254.77 MPa and the critical strains were 0.022–0.044. The facts show that the boron-containing phase of BSS prevented the onset of DRX, despite the saturated boron in the austenite initiated DRX. The microstructural analysis showed that hot deformation promoted the generation of borides, which differed from the initial microstructure of HIP. The inhomogeneous distribution of elements in the boron-containing phase was caused by hot compression.

Producing HP Pump Barrels Utilizing Powder Metallurgy and Hot Isostatic Pressing

2009 ◽  
Author(s):  
Martin Bjurstro¨m ◽  
Carl-Gustaf Hjorth
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Hot Isostatic Pressing ◽  
Austenitic Stainless Steels ◽  
Pressure Vessels ◽  
Uniform Structure ◽  
Isostatic Pressing ◽  
Near Net Shape ◽  
Hip Process

The fabrication of near net shape powder metal (PM) components by hot isostatic pressing (HIP) has been an important manufacturing technology for steel and stainless steel alloys since about 1985. The manufacturing process involves inert gas atomization of powder, 3D CAD capsule design, sheet metal capsule fabrication and densification by HIP in very large pressure vessels. Since 1985, several thousand tonnes of parts have been produced. The major applications are found in the oil and gas industry especially in offshore applications, the industrial power generation industry, and traditional engineering industries. Typically, the components replace castings, forgings and fabricated parts and are produced in high alloy grades such as martensitic steels, austenitic stainless steels, duplex (ferritic/austenitic) stainless steels and nickel based superalloys. The application of PM/HIP near net shapes to pump barrels for medium to high pressure use has a number of advantages compared to the traditional forging and welding approach. First, the need for machining of the components is reduced to a minimum and welding during final assembly is reduced substantially. Mechanical properties of the PM/HIP parts are isotropic and equal to the best forged properties in the flow direction. This derives from the fine microstructure using powder powder and the uniform structure from the HIP process. Furthermore, when using the PM HIP process the parts are produced near net shape with supports, nozzles and flanges integrated. This significantly reduces manufacturing lead-time and gives greater design flexibility which improves cost for the final component. The PM HIP near net shape route has received approval from ASTM, NACE and API for specific steel, stainless steel and nickel base alloys. This paper reviews the manufacturing sequence for PM near net shapes and discusses the details of several successful applications. The application of the PM/HIP process to high pressure pump barrels is highlighted.

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