Effect of Heat Treatment on Corrosion Properties of Selective Laser Melted Stainless Steel Parts

2018 ◽  
Author(s):  
Sagar Sarkar ◽  
Saumya Ranjan Jha ◽  
Ashish Kumar Nath
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Metal Powders ◽  
Solution Annealing ◽  
Corrosion Properties ◽  
Pitting Potential ◽  
Suitable Heat Treatment ◽  
Inhomogeneous Microstructure ◽  
Over Time

One of the most popular additive manufacturing processes among today’s manufacturing industries is Selective Laser Melting (SLM) in which very intricate shapes can be fabricated directly from its three dimensional digital design data by melting metal powders using laser. Layer by layer deposition of material about different build axes make SLM parts anisotropic in nature. Also, non-uniformity in thermal loading at top and bottom surfaces of a SLM part leads to inhomogeneous microstructure and may change electro-chemical properties across the part. Suitable heat treatment as a post processing technique can reduce this anisotropy and produce homogeneous microstructure leading to reproducible mechanical and electrochemical properties. Depending upon the application in actual industrial scenarios, SLM parts may be subjected to corrosive media and thus may affect service life of the part. In the present study, effect of different heat treatment namely solution annealing, ageing, overaging on corrosion properties of SLM 15-5 Precipitation-Hardened (PH) stainless steel have been studied. Various metallurgical characterizations have been carried out wherever required to support experimental observations. As-built specimens have approximately six times higher pitting potential which may be attributed to higher nitrogen content present in as-built specimens but corrode more over time than solution annealed (SA) specimens. Relatively bigger size pits and non-uniformity in their distributions can be attributed to residual stresses and inhomogeneous microstructure associated with as-built SLM specimens respectively. Specimen undergone standard ageing condition (H900) corrodes least over time among all the heat treatment conditions considered in the present study. However, in this case, a large number of shallow pits can be observed from the corroded surface. Overaged (H1150) specimens corrode more than H900 specimens but pitting starts late in case of H1150 specimens since pitting potential is almost ten times higher in the former case. Increased ageing temperature and soaking time (Mod H900 (SA)) increases formation of higher Cr23C6 precipitates than that of H900 condition and hence corrode more over time. Ageing without solution annealing (Mod H900 (AB)) leads to higher corrosion and larger pit size non-uniformly distributed over the corroded surface than that of Mod H900 (SA) condition which may be attributed to presence of residual stresses and non-uniform precipitation throughout the matrix. Present study will be useful for selecting suitable heat treatment yielding desired corrosion resistance for SLM stainless steel parts.

Effect of Heat Treatment on Impact Toughness of Selective Laser Melted Stainless Steel Parts

2018 ◽  
Author(s):  
Sagar Sarkar ◽  
Soumya Dubey ◽  
Ashish Kumar Nath
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Impact Toughness ◽  
Thermal Loading ◽  
Processing Technique ◽  
Layer By Layer ◽  
Solution Annealing ◽  
Tem Analysis ◽  
Suitable Heat Treatment

One of the versatile additive manufacturing processes is laser based Selective Laser Melting (SLM) which allows to build complex intricate shapes directly from its three dimensional digital images. Layer by layer deposition and depending upon build orientations, SLM parts tends to be anisotropic in nature. Also non-uniformity in thermal loading across the part leads to inhomogeneous microstructure which may have detrimental effect on various mechanical properties. Heat treatment of as-built SLM parts could be used as a post processing technique to reduce the anisotropy and produce homogenous microstructure to ensure reproducible mechanical properties. Application oriented mechanical properties can be obtained for precipitation hardened stainless steel by suitable heat treatment process. Present study is based on effect of heat treatments namely solution annealing, ageing and overaging on impact toughness of SLM 15-5 PH stainless steel. In order to support experimental observations, various metallurgical techniques have been applied. Effect of notch orientations causes anisotropy in impact toughness but this anisotropy is reduced with application of suitable heat treatment. In case of ageing, Transmission Electron Microscopy (TEM) analysis shows formation of fine spherical Cu precipitates which solution strengthens but makes the specimen brittle. As a result relatively lower impact toughness is obtained as compared to overaged condition where combined effect of coarsening of Cu precipitates and increased retained austenite makes the specimen ductile. Increased ageing temperature and soaking time does not have significant effect on impact toughness. However, solution annealing before ageing is recommended for homogenous precipitation throughout the specimen and statistically less scattered data. In all the cases SLM specimens have lower impact toughness to that of cold rolled 15-5 PH stainless steel. Present study could be used as a guideline to get application oriented mechanical properties mainly impact toughness.

scholarly journals Effect of heat treatment on the microstructure and corrosion properties of cast duplex stainless steels

2021 ◽  
Vol 225 ◽  
pp. 01003
Author(s):  
Aleksandr Fedorov ◽  
Andrey Zhitenev ◽  
Darya Strekalovskaya
Keyword(s):  
Heat Treatment ◽  
Experimental Study ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Formation Processes ◽  
Corrosion Properties ◽  
Quenching Temperature ◽  
Pitting Potential ◽  
Pitting Corrosion Resistance

The effect of the quenching temperature on the pitting corrosion resistance of lean duplex stainless steel (DSS) were examined. Using thermodynamic modeling of phase formation processes in steel during solidification and subsequent cooling was shown that the equal amount of austenite and ferrite is achieved at 1210°С for examined composition. Experimental steel samples were quenched from 1100 and 1200°С. It was found that as the temperature rises, the pitting potential increases significantly due to the achievement of a favorable phase ratio. The results of this experimental study made it possible to develop a heat treatment that provides high corrosion properties of lean DSS.

scholarly journals Effect of Aging Heat Treatment H950 and H1000 on Mechanical and Pitting Corrosion Properties of UNS S46500 Stainless Steel

2018 ◽  
Vol 22 (1) ◽  
Author(s):  
Camila Haga Beraldo ◽  
José Wilmar Calderón-Hernández ◽  
Rodrigo Magnabosco ◽  
Neusa Alonso-Falleiros
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Pitting Corrosion ◽  
Corrosion Properties ◽  
Aging Heat Treatment

scholarly journals Through-Thickness Residual Stresses, Microstructure, and Mechanical Properties of Electron Beam-Welded CA6NM Martensitic Stainless Steel after Postweld Heat Treatment

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Sheida Sarafan ◽  
Priti Wanjara ◽  
Jean-Benoît Lévesque ◽  
Javad Gholipour ◽  
Henri Champliaud ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Electron Beam ◽  
Residual Stresses ◽  
Tensile Properties ◽  
Martensitic Stainless Steel ◽  
Postweld Heat Treatment ◽  
Image Correlation ◽  
Postweld Heat

In this study, the integrity of electron beam- (EB-) welded CA6NM—a grade of 13% Cr-4% Ni martensitic stainless steel—was assessed through the entire joint thickness of 90 mm after postweld heat treatment (PWHT). The joints were characterized by examining the microstructure, residual stresses, global mechanical properties (static tensile, Charpy impact, and bend), and local properties (yield strength and strain at fracture) in the metallurgically modified regions of the EB welds. The applied PWHT tempered the “fresh” martensite present in the microstructure after welding, which reduced sufficiently the hardness (<280 HV) and residual stresses (<100 MPa) to meet the requirements for hydroelectric turbine assemblies. Also, the properties of the EB joints after PWHT passed the minimum acceptance criteria specified in ASME sections VIII and IX. Specifically, measurement of the global tensile properties indicated that the tensile strengths of the EB welds in the transverse and longitudinal directions were on the same order as that of the base metal (BM). Evaluation of the local tensile properties using a digital image correlation (DIC) methodology showed higher local yield strengths in the fusion zone (FZ) and heat-affected zone (HAZ) of 727 MPa and 740 MPa, respectively, relative to the BM value of 663 MPa. Also, the average impact energies for the FZ and HAZ were 63 J and 148 J, respectively, and attributed to the different failure mechanisms in the HAZ (dimples) versus the FZ (quasi-cleavage consisting of facets and dimples). This study shows that the application of PWHT plays an important role in improving the weld quality and performance of EB-welded CA6NM and provides the essential data for validating the design and manufacturing process for next-generation hydroelectric turbine products.

Effect of post-weld heat treatment on microstructure and corrosion properties of multi-layer super duplex stainless steel welds

2021 ◽  
Vol 63 (9) ◽  
pp. 791-796
Author(s):  
Lei Tian ◽  
Zhanqi Gao ◽  
Yongdian Han
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Welded Joints ◽  
Post Weld Heat Treatment ◽  
Super Duplex Stainless Steel ◽  
Corrosion Properties ◽  
Austenite Content ◽  
Mechanical And Corrosion Properties ◽  
Weld Heat

Abstract To investigate the influence of post-weld heat treatment on the microstructure and corrosion properties of super duplex stainless steel welded joints, multi-layer multi-pass welding of 2507 super duplex stainless steel by tungsten argon arc welding was performed using an ER2594 welding wire. The microstructures of the welded joints before and after post-weld heat treatment at 1150 °C, 1170 °C and 1190 °C were observed, and the mechanical and corrosion properties were tested. The post-weld heat treatment changed the austenite content and morphology of the welded joint and improved the corrosion resistance of different parts of the weld metal. The choice of various solution heat treatment temperatures affected the change in austenite content in the weld zone and the degree of diffusion and homogenization of the alloy elements. After post-weld heat treatment at 1170 °C, the two-phase ratios in each area of the weld were the most suitable and uniform, and the overall mechanical and corrosion properties of the joint were more uniform.

Residual Stress Measurements and Modelling for Temper Bead Qualification

2013 ◽  
Author(s):  
Xavier Ficquet ◽  
Vincent Robin ◽  
Ed Kingston ◽  
Stéphan Courtin ◽  
Miguel Yescas
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Hole Drilling ◽  
Stainless Steel Surface ◽  
Element Analysis ◽  
Stress Measurements ◽  
Welding Processes

This paper presents results from a programme of through thickness residual stress measurements and finite element analysis (FEA) modelling carried out on a temper bead mock-up. Emphasis is placed on results comparison rather than the measurement technique and procedure, which is well documented in the accompanying references. Temper bead welding processes have been developed to simulate the tempering effect of post-weld heat treatment and are used to repair reactor pressure vessel components to alleviate the need for further heat-treatment. The Temper Bead Mock-up comprised of a rectangular block with dimension 960mm × 189mm × 124mm was manufactured from a ferritic steel forged block with an austenitic stainless steel buttering and a nickel alloy temper bead cladding. The temper bead and buttering surfaces were machined after welding. Biaxial residual stresses were measured at a number of locations using the standard Deep-Hole Drilling (DHD) and Incremental DHD (iDHD) techniques on the Temper Bead Mock-up and compared with FEA modelling results. An excellent correlation existed between the iDHD and the modelled results, and highlighted the need for the iDHD technique in order to account for plastic relaxation during the measurement process. Maximum tensile residual stresses through the thickness were observed near the austenitic stainless steel surface at 298MPa. High compressive stresses were observed within the ferritic base plate beneath the bimetallic interface between austenitic and ferritic steels with peak stresses of −377MPa in the longitudinal direction.

Mechanical and Corrosion Properties of Ni-Free Austenitic Stainless Steel/Hydroxyapatite Nanocomposites

2009 ◽  
Vol 151 ◽  
pp. 213-216 ◽  
Author(s):  
Maciej Tulinski ◽  
Mieczyslaw Jurczyk
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Bulk Material ◽  
Hard Tissue ◽  
Corrosion Properties ◽  
Ringer’S Solution ◽  
Tissue Replacement ◽  
Mechanical And Corrosion Properties

In the present work, a nanocrystalline nickel-free stainless steels as well as nickel-free stainless steel/hydroxyapatite nanocomposites have been synthesized by the combination of mechanical alloying (MA), heat treatment and nitriding. The microhardness of the final bulk material was studied using Vickers method. Corrosion potentiodynamic tests were performed in Ringer’s solution. The results show that nickel-free stainless steel/hydroxyapatite nanocomposites could be promising bionanomaterials for use as a hard tissue replacement implants.

Influence of Chromium Carbide Size on the Austenitization Kinetics of a Martensitic Stainless Steel Measured by Dilatometry

2011 ◽  
Vol 172-174 ◽  
pp. 426-431 ◽  
Author(s):  
Valérie Kostoj ◽  
Jean Denis Mithieux ◽  
Thomas Fröhlich
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Treatment Time ◽  
Essential Point ◽  
Suitable Heat Treatment ◽  
Batch Annealing ◽  
Industrial Material ◽  
Different Temperatures ◽  
Kinetics Of

The use of martensitic stainless steels is commonly due to high mechanical properties requirements. To obtain these high values from the industrial material (whose microstructure consists in ferrite and M23C6carbides), a suitable heat treatment, consisting in an austenitization of the steel at a temperature higher than A3 point, followed by a fast quenching, is necessary. For economic reasons, the shortest the heat treatment time, the better it will be. Therefore, one essential point, to reduce austenitization time, is to obtain a final product made of ferrite and carbides, with the lowest carbides size as possible: the lowest they will be, the shortest time the transformation ferrite + carbides --> austenite will take. The formation of these carbides occurs during the batch annealing of the steel, at low temperature. To study the influence of carbides size on the austenitization kinetics of a 1.4006 grade martensitic stainless steel, several batch annealings were made at different temperatures. Carbides sizes were measured by electronic microscopy and austenitization kinetics were measured by dilatometry. Small carbides size logically induces fastest austenitization kinetics. The austenization occurs in three stages: a fast one which corresponds to the dissolution of the smallest carbides leading to a homogeneous repartition of carbon, a chromium gradient into ferrite and thus an austenitization until reaching Cr-rich ferrite. The second one is limited by the diffusion of chromium, inducing a slower transformation. The apparent third stage is an artefact of the second one, as it corresponds to an expansion of the austenite due to the diffusion of carbide, and an apparent increase of the transformation kinetics.

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