Tensile and Fracture Properties of X80 Steel Microstructures Relevant to the HAZ

2012 ◽  
Author(s):  
Michael J. Gaudet ◽  
Warren J. Poole
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Pipeline Steel ◽  
Thin Sheet ◽  
Detailed Knowledge ◽  
Tear Strength ◽  
Heat Treated ◽  
The Individual ◽  
Unit Propagation ◽  
Tensile Toughness

The girth welding of steel pipelines creates a substantial heat affected zone (HAZ) within the base pipeline steel. The HAZ can be considered to be a complex graded microstructure. While there is significant concern as to the fracture and mechanical properties of the HAZ as whole, detailed knowledge about the mechanical properties of the individual microstructures is lacking. For this study, X80 is heat treated in a Gleeble simulator to create samples of bulk microstructures with differing amounts and morphologies of bainite, ferrite and martensite-retained austenite (MA) with a total of 8 microstructures being investigated. The heat treatments were selected specifically to control the level of niobium in solid solution; that is to control whether niobium was fully in solution or contained mainly in niobium carbonitride precipitates. From the heat treated samples a matching tensile and fracture specimens were made. The strongest microstructure proved to be the finest bainitic microstructure, while the lowest strength microstructure was the coarsest bainite sample containing a significant amount of martensite-retained austenite connected along grain boundaries. The fracture behaviour at ambient temperature was studied using the Kahn tear test. The Kahn tear test is a machine notched, thin-sheet, slow strain rate fracture test which has the advantage of being a simple test to conduct. All Kahn tests failed in a ductile manner and it showed that the sample with the coarse bainite, with a connected martensite-retained austenite phase had the lowest unit propagation energy and tear strength while the fine, fully bainitic sample had the highest unit propagation energy and tear strength. Further investigation using SEM measurements of the final fracture surface from the tensile test to determine the tensile toughness. A comparison of the tensile toughness and unit propagation energies showed that there was a complex relationship between the two measurements. However, the samples which had the highest content of MA gave the in lowest unit propagation energy.

Effects of Cryogenic Treatment on the Microstructure and Mechanical Properties of High-alloyed Tool Steels

2020 ◽  
Vol 75 (5) ◽  
pp. 73-93
Author(s):  
Alwin Schulz ◽  
Chengsong Cui ◽  
Matthias Steinbacher ◽  
Tuncer Ümit ◽  
Martin Wunde ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Homogeneous Distribution ◽  
Tool Steels ◽  
Positive Effects ◽  
Heat Treated ◽  
Primary Carbides ◽  
Complete Transformation

Abstract In this work, the influence of a cryogenic treatment on the microstructure, mechanical properties and wear resistance of the high-alloyed tool steels X38CrMoV5-3, X153CrMoV12 and ~X190CrVMo20-4 were investigated. Based on tempering curves of the steels, the heat treatment parameters were determined for the mechanical and wear specimens so that the conventionally heat-treated steels and the cryogenically treated steels featured similar hardness. The investigations showed that an almost complete transformation of retained austenite and a more homogeneous distribution of secondary carbides in the microstructure could be achieved by incorporating a cryogenic treatment. However, the cryogenic treatment does not show significantly positive effects on the investigated mechanical properties and wear resistance of the tool steels. The wear resistance of the samples was dominated by primary carbides. The cryogenic treatment would have a positive effect on large tool components with large wall thicknesses in terms of uniform and complete transformation of retained austenite throughout the entire components.

Study of Hydrogen Permeation in a Micro-Alloyed Heat Treated Steel

2014 ◽  
Vol 353 ◽  
pp. 165-170 ◽  
Author(s):  
N. Lopez-Perrusquia ◽  
Marco Antonio Doñu-Ruíz ◽  
J.A. Ortega-Herrera ◽  
G. Urriolagoitia-Calderón ◽  
Yahir Edgar Vargas-Oliva
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Hydrogen Permeation ◽  
Pipeline Steel ◽  
Optical Analysis ◽  
Treated Steel ◽  
Heat Treated ◽  
Point Test ◽  
Heat Treated Steel ◽  
Type Of Fracture

In this work, an experimental research was conducted to determine of effects hydrogen permeation a micro-alloyed heat treatment steel in order to determine the mechanical properties of the material in this work [1]. Small specimens were taken from the micro-alloyed API-X60 steel. Moreover, by the technique of the three-point test according to ASTM 399-90, the load-displacement curves for each heat treatment with and without hydrogen permeation are determined. Likewise the samples were then mechanically tested for hardness by the technique of nanoindentation to obtain the elastic modulus and hardness of the studied specimens [2]. Scanning electron microscopy (SEM) determines the type of fracture; also EDS revealed the type of precipitate formed in the surface of the material [3]. The optical analysis showed the following microstructures; ferrite/pearlite, bainite/ferrite and martensite/retained-austenite [4]. Finally the experimental and statistical results showed effect of hydrogen permeation and heat treatment on the mechanical properties of the micro-alloyed API X-60 grade pipeline steel.

scholarly journals Process optimization of the mechanical properties of AISI 1020 steel quenched using maize-stover ash potash solution

2020 ◽  
Vol 39 (3) ◽  
pp. 821-829
Author(s):  
O.I. Ogunwede ◽  
M.S. Abolarin ◽  
A.S. Abdulrahman ◽  
O.A. Olugboji ◽  
J.B. Agboola ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Maize Stover ◽  
Test Pieces ◽  
Weighted Analysis ◽  
Orthogonal Array Method ◽  
Treated Steel ◽  
Heat Treated ◽  
Analysis Technique ◽  
The Individual ◽  
Heat Treated Steel

The process parameter optimization of maize-stover ash potash (MSAP) as a quenching medium for heat treatment of AISI-1020 steel was conducted in this study to improve the mechanical properties of steel after carburization and quenching. The optimization process utilized Taguchi L9(32) orthogonal array method to determine the individual Signal to Noise (S/N) ratio and Analysis of Variance (ANOVA). A multi-response weighted analysis technique was applied to derive combined quality responses of the heat treated test pieces. The result shows that the optimal factor level of MSAP solution strength was achieved at AM1BM1, which offered 57.6 HRC hardness, 39 J toughness and 1971 N/mm2 tensile strength as improved mechanical properties for the heat treated steel. Keywords: Optimization, MSAP, quenching, Taguchi, ANOVA

scholarly journals Assessment of Retained Austenite in Fine Grained Inductive Heat Treated Spring Steel

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4063 ◽  
Author(s):  
Anna Olina ◽  
Miroslav Píška ◽  
Martin Petrenec ◽  
Charles Hervoches ◽  
Přemysl Beran ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cross Section ◽  
Retained Austenite ◽  
Quantitative Assessment ◽  
Spring Steel ◽  
Rapid Phase ◽  
Fine Grained ◽  
The Core ◽  
Heat Treated

Advanced thermomechanical hot rolling is becoming a widely used technology for the production of fine-grained spring steel. Different rapid phase transformations during the inductive heat treatment of such steel causes the inhomogeneous mixture of martensitic, bainitic, and austenitic phases that affects the service properties of the steel. An important task is to assess the amount of retained austenite and its distribution over the cross-section of the inductive quenched and tempered wire in order to evaluate the mechanical properties of the material. Three different analytical methods were used for the comparative quantitative assessment of the amount of retained austenite in both the core and rim areas of the sample cross-section: neutron diffraction—for the bulk of the material, Mössbauer spectroscopy—for measurement in a surface layer, and the metallographic investigations carried by the EBSD. The methods confirmed the excessive amount of retained austenite in the core area that could negatively affect the plasticity of the material.

On the Relationship of Microstructure, Toughness, and Hardness Properties in a Submerged Arc Welded API-5L Grade X65 Pipeline Steel Section

2014 ◽  
Author(s):  
Lee Aucott ◽  
Shuwen Wen ◽  
Hongbiao Dong
Keyword(s):  
Mechanical Properties ◽  
Fusion Zone ◽  
Base Metal ◽  
Weld Joint ◽  
Small Volume ◽  
Pipeline Steel ◽  
Chemical Properties ◽  
Detailed Knowledge ◽  
Upper Bainite ◽  
Submerged Arc

In order to further improve welded pipeline performance, a detailed knowledge of the key and interlinking relationships between the chemistry, microstructure and mechanical properties of the weld joint is needed. In this paper, the results of optical emission spectroscopy analysis on the as welded chemical properties of a submerged arc welded API-5L grade X65 linepipe are first presented. The microstructure of the various weld regions is then assessed against the results of the chemical analysis using a series of microscopy techniques. A fine grained ferrite-degenerate pearlite microstructure was observed within the base metal of the linepipe along with large (1.5 μm) cuboidal Ti (C, N) precipitates. Within the heat affected zone (HAZ) close to the molten weld joint, grain growth occurred with small volume fractions of induced upper bainite present within the microstructure. The fusion zone of the submerged arc weld joint consists of predominantly acicular ferrite with a small volume of grain boundary phases and a high number of large (0.8 μm) spherical Ti (C, N) precipitates. The results of Vickers hardness tests carried out at two length scales (macro + micro) show clear relations between the hardening effects of the cementite enriched degenerate pearlite and induced upper bainite phases within the base metal and HAZ respectively. Fractography analysis of Charpy impact test samples across the submerged arc welded joint found that the large Ti (C, N) precipitates within the fusion zone appear to be acting as microvoid initiation sites for the ductile fracture and as such contributing to the relatively low toughness properties within the fusion zone. Finally, the potential benefits of reducing the Ti content in both the welding wires and X65 base metal for further improvement of the mechanical properties of the linepipe weld joint are discussed in regards to reducing the size of the coarse Ti (C, N) precipitates within the base metal, HAZ and fusion zone.

Influence of the Order of Incorporation of Sulfur in the Mechanical Properties of Vulcanized Nr Compounds

2020 ◽  
Vol 1012 ◽  
pp. 62-66
Author(s):  
Kleber Vaccioli ◽  
Samuel Marcio Toffoli ◽  
Ticiane Sanches Valera
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Dimensional Stability ◽  
Maximum Elongation ◽  
Mixing Process ◽  
Tear Strength ◽  
Rubber Compounds ◽  
Sulfur Addition ◽  
Heat Treated ◽  
Process Method

The objective of this work was to evaluate the influence of the order of sulfur addition on the mechanical properties of vulcanized natural rubber compounds. The addition of sulfur was carried out by two methodologies: (I) sulfur was added at the beginning of the mastication process, and (II) sulfur was added at the end of the mixing process. The compounds were obtained in open cylinder, and vulcanized in a press at 150°C. The vulcanization parameters were determined by rheometry, where as the mechanical properties were evaluated by testing samples for their tensile strength, tear strength, resilience, and Shore-A hardness. The dimensional stability of the vulcanized samples was also evaluated experimentally, by comparing specimens not heat-treated to those submitted to 100°C for 4 hours. Comparing the results of method (I) to method (II), the results, indicate that the addition of sulfur at the beginning of the mastication process (method I) yielded increases of 20 and 11% in tensile strength and tear strength, respectively, followed by a 9% increase in hardness, and 6% in resilience, without significant losses in maximum elongation. The dimensional stability test showed a reduction of 75% in the contraction for the vulcanized samples which had sulfur addition at the beginning of the mastication process of the unvulcanized NR rubber.

Influence of Low Tempering Temperature on Fracture Toughness of Ultra High Strength Boron Steel for Hot Forming

2010 ◽  
Vol 146-147 ◽  
pp. 160-165 ◽  
Author(s):  
Liang Ying ◽  
Ying Chang ◽  
Ping Hu ◽  
Guo Zhe Shen ◽  
Li Zhong Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Strength ◽  
Hot Forming ◽  
Boron Steel ◽  
Temper Brittleness ◽  
Tempering Temperature ◽  
Tear Strength ◽  
Quenched Steel ◽  
Unit Propagation

The influence of low tempering temperature (TT) on mechanical properties and fracture toughness of ultra high strength boron steel 22MnB5 for hot forming was investigated by tensile and Kahn tearing experiments. Compared with the conventional quenchable boron steel, The results show that the toughness of tested steel are both preferable when tempered at 200 , 40min. When TT between 100 ～200 , The tear strength (TS) and unit propagation energy (UPE) of quenched steel heightened along with the temperature raised, but in 200~350 temperature range, the toughness appears negatively growth. Appropriate TT could improve the mechanical properties and fracture toughness obviously, and the temper brittleness can be avoided.

scholarly journals Influence of Tempering on Mechanical Properties of Induction Bents below 540°C

2016 ◽  
Vol 10 (2) ◽  
pp. 81-86 ◽  
Author(s):  
Peter Jankejech ◽  
Peter Fabian ◽  
Jozef Broncek ◽  
Yuriy Shalapko
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Hsla Steel ◽  
Straight Pipe ◽  
Basic Principles ◽  
Heat Treated ◽  
Tensile Toughness

Abstract The article describes basic principles of induction bending and the change of mechanical properties from as received (straight) pipe made from HSLA steel to induction bend. The main purpose of this article is to experiment with tempering temperatures below 540°C. After tempering at 540°C which is the lowest recommended temperature for post bend heat treatment (PBHT) according to CSA specifications (Canadian Standards Association) the induction bend area in many cases does not achieve the minimum required mechanical properties and therefore it is not accepted for usage. In this article mechanical properties such as tensile, toughness, hardness are evaluated. Also the article contains microstructural analyses and comparison of bended and heat treated samples.

Crystallographic Texture of Induction-Welded and Heat-Treated Pipeline Steel

2010 ◽  
Vol 89-91 ◽  
pp. 651-656 ◽  
Author(s):  
P. Yan ◽  
Özlem Esma Güngör ◽  
Philippe Thibaux ◽  
Harshad K.D.H. Bhadeshia
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Treatment Process ◽  
Pipeline Steel ◽  
Large Diameter ◽  
Seam Welding ◽  
Steel Pipes ◽  
Simple Observation ◽  
Heat Treated

Large-diameter steel pipes are produced by induction seam-welding followed by induction-assisted heat treatment. The microstructure and distribution of crystal orientations have been studied and related to the mechanical properties of the welded regions. The welding and heat-treatment process leads to a microstructure, a simple observation of which can not explain the observed variations in toughness in the vicinity of the welding joint, because the crystallographic grain size, which represents the scale of similarly oriented adjacent grains, is much coarser than the ordinary grain size. Furthermore, heating the affected zone into the austenite phase field followed by cooling does not completely eliminate the coarse regions of similarly oriented grains. The consequences of this on mechanical properties are discussed.

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