The Effect of Heat Treatment on Formability of Ultra-Fine Grained AA6061 for Bolt Manufacturing

2010 ◽  
Vol 443 ◽  
pp. 164-169 ◽  
Author(s):  
Jun Seok Choi ◽  
Young Gwan Jin ◽  
Yong Taek Im
Keyword(s):  
Heat Treatment ◽  
Artificial Aging ◽  
Equal Channel Angular Extrusion ◽  
High Strength ◽  
Strength Increase ◽  
Fine Grained ◽  
Heat Treated ◽  
Before And After ◽  
Fine Grained Material ◽  
Set Up

Equal channel angular extrusion (ECAE) was used before and after artificial aging to investigate the effect of heat treatment on formability of bulk nanostructure of commercially available aluminum alloy of AA6061 in the present study. In the ECAE, route A was applied up to four or eight passes by using the split dies set-up. The three-stage bolt forming using the ultra-fine grained specimens was carried out to check formability of the material. In the present experiments, the bolt forming was successful with the specimen prepared by the ECAE after artificial aging whilst it was not successful with the specimen prepared by a reverse process sequence. The strength increase was confirmed by the tension and microhardness tests and compared to the result of conventional AA2024 bolt made by the conventionally heat treated specimen. It was found that the strength was comparable to the level of the heat treated conventional one although the actual value was a little bit lower. In addition, it was demonstrated that the heat treatment sequence is important to achieve proper formability of the ultra-fine grained material to manufacture the high strength bolt.

Casting and Heat Treatment of Turbocharger Impellers Thixocast from Alloy 201

2012 ◽  
Vol 192-193 ◽  
pp. 556-561 ◽  
Author(s):  
Qiang Zhu ◽  
Stephen Midson ◽  
Chang Wei Ming ◽  
Helen V. Atkinson
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
Heat Treatment Condition ◽  
Hot Tearing ◽  
Alloy Casting ◽  
Heat Treated ◽  
Before And After ◽  
Optimum Heat ◽  
Semi Solid ◽  
Optimum Heat Treatment

Commercial semi-solid cast impellers are produced from Al-Si-Cu alloys heat treated to the T6 temper. The study described in this paper involved the identification of casting and heat treatment parameters to produce semi-solid processed turbocharger impellers from a silicon-free, higher strength 201 alloy. Casting parameters were identified which minimized hot tearing in the alloy 201 impellers. A series of heat treatment studies were performed to determine optimum heat treatment parameters. The T71 temper was identified as the preferred heat treatment condition to produce high strength as well as superior elongation. The results from mechanical property measurements conducted on the T71 heat treated impellers are reported. Optical and scanning electron microscopy (SEM) were also used to characterize the microstructure of alloy 201 impellers before and after heat treatment, and representative microstructures are presented.

Effects of a Thermal Coating Process on X100 UOE Line Pipe

2005 ◽  
Author(s):  
Chris Timms ◽  
Duane DeGeer ◽  
Martin McLamb
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Room Temperature ◽  
High Strength ◽  
Economic Benefits ◽  
Slight Reduction ◽  
Strength Increase ◽  
Coating Process ◽  
Line Pipe ◽  
Heat Treated

The increased demand for high strength linepipe for onshore and offshore pipeline systems has been well documented over the past few years. The economic benefits have been demonstrated, and solutions have been developed to address the technical issues facing high strength linepipe use. However, there are still a few unanswered questions, one of which is addressed in this paper: what is the effect of thermal treatment during the pipeline coating process on the material behaviour of high strength linepipe? This paper presents the results of a thermal coupon study investigating the effects of low temperature heat treatment on the tensile and compressive stress strain curves of samples taken from X100 linepipe. Thirty axial test coupons and thirty circumferential test coupons were machined from a 52 inch diameter, 21 mm wall thickness UOE X100 linepipe. Some of the coupons were maintained in the as-received condition (no heat treatment) while others were heat-treated in a manner that simulates a coating plant induction heat treatment process. All coupons were subsequently tested in tension or compression, either at room temperature or at −18°C. This study has provided a number of interesting results. In regards to material strength, the heat treatment increased the tensile and compressive yield strengths in the longitudinal and circumferential coupons. Axial tensile, axial compressive and circumferential tensile yield strength increases ranged from 5 to 10%. Circumferential compressive yield strength increases ranged from 14 to 24%. A Y/T ratio increase of approximately 7% was observed for all heat-treated tensile coupons. The coupon tests conducted at −18°C were only slightly different than their room temperature counterparts; with an average yield strength increase of 4% in all directions and orientations and a slight reduction in Y/T ratio.

scholarly journals Hydrogen Embrittlement of the Additively Manufactured High-Strength X3NiCoMoTi 18-9-5 Maraging Steel

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5073
Author(s):  
Angelina Strakosova ◽  
Michaela Roudnická ◽  
Ondřej Ekrt ◽  
Dalibor Vojtěch ◽  
Alena Michalcová
Keyword(s):  
Heat Treatment ◽  
Hydrogen Embrittlement ◽  
Maraging Steel ◽  
Tensile Testing ◽  
High Strength ◽  
Fracture Surface Morphology ◽  
Laser Melting ◽  
Heat Treated ◽  
Before And After ◽  
A Current

The main aim of this study was to determine the susceptibility of the additively manufactured high strength X3NiCoMoTi 18-9-5 maraging steel to hydrogen embrittlement. For this purpose, samples produced by selective laser melting technology, before and after heat treatment, were used. The examined samples were electrochemically charged with hydrogen in NaCl + NH4SCN solution at a current density of 50 mA/cm2 for 24 h. The H content increased from about 1 to 15 ppm. Heat treatment did not affect the amount of H trapped in the maraging steel. Tensile testing revealed that the tensile strength of the H-charged samples was much lower than that of the uncharged samples. Moreover, the material became brittle after charging compared to the ductile as-printed and heat-treated samples with elongation values of 7% and 2%, respectively. The loss of plasticity was confirmed by fractography, which revealed transformation of the fracture surface morphology from dimple-like in the as-produced state to a brittle one with smooth facets in the H-charged state.

scholarly journals Combining Equal-Channel Angular Extrusion (ECAE) and Heat Treatment for Achieving High Strength and Moderate Ductility in an Al-Cu Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 685-690 ◽  
Author(s):  
Matthias Hockauf ◽  
Lothar W. Meyer ◽  
Lutz Krüger
Keyword(s):  
Heat Treatment ◽  
Equal Channel Angular Extrusion ◽  
Failure Strain ◽  
Solution Treatment ◽  
High Strength ◽  
Ultimate Tensile Stress ◽  
Processing Temperature ◽  
Strength Increase ◽  
High Temperature Short Time ◽  
Angular Extrusion

The effect of equal-channel angular extrusion (ECAE) on mechanical properties of an AA2017 produced by powder metallurgy is investigated. Special attention is given to the influence of heat treatment, processing temperature and backpressure on the workability for achieving high strength and moderate ductility. This is of special interest, since it is often reported that Al-Cu alloys have low ductility and therefore are prone to cracking during severe plastic deformation. It is shown that ECAE at high temperatures (>220°C) does not necessitate backpressure to ensure homogeneous deformation but leads to a significant sacrifice in strength due to in-situ precipitation. Thus, most of the extrusions are done at considerably low temperatures. Performing room temperature-extrusion is most effective in achieving high strengths but also requires high backpressures. Due to severe strain hardening during processing, the strength increase is combined with a reduction in ductility. Recently it was reported that a post-ECAE aging of pre-ECAE solution treated material is effective in enhancing the ductility of aluminium alloys. This approach was successfully transferred to the current alloy. A high-temperature, short-time aging after only one extrusion, for example, doubles the failure strain to a value of ~13%. Compared to the naturally aged condition with coarse grains that serves as reference (T4), an increase of 15 % in yield stress (YS) was obtained while retaining the ultimate tensile stress (UTS). Another effective approach is the combination of a pre-ECAE solution treatment with subsequent under-aging prior to ECAE. It is shown that performing ECAE at medium temperatures (160-180°C) enables a better workability and additionally gives higher strengths and better ductility compared to the processing in the water quenched condition. A remarkable YS of 530 MPa and an UTS of 580 MPa combined with a moderate failure strain of 11.6 % were achieved.

Application of Tailored Heat Treated Blanks under Quasi Series Conditions

2007 ◽  
Vol 344 ◽  
pp. 383-390 ◽  
Author(s):  
Marion Merklein ◽  
Uwe Vogt
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Local Heat ◽  
Strength Distribution ◽  
Process Window ◽  
Short Term ◽  
Forming Process ◽  
Heat Treated ◽  
Set Up ◽  
The Impact

Tailored Heat Treated Blanks (THTB) are blanks that exhibit locally different strength specifically optimized for the succeeding forming process. The strength distribution is set by a local, short-term heat treatment modifying the mechanical properties of the material. Hence, THTB allow enhancing forming limits significantly leading to shorter and more robust manufacture process chains. In order to qualify the use of THTB under quasi series conditions, the interdependencies of the blank’s local heat treatment and the entire process chain of the car body manufacture have to be analyzed. In this respect, the impact of a short-term heat treatment on the mechanical properties of AA6181PX, a commonly used aluminum alloy in today’s car bodies, was studied. Also the influence of a short-term heat treatment on the coil lubricant, usually already applied by the material supplier, was given a closer look. Based on these experiments process restrictions for the application of THTB in an industrial automotive environment were derived and a process window for the THTB design was set up. In conclusion, strategies were defined how to enhance the found process boundaries leading to a more robust process window.

Comparison of Microstructure and Mechanical Properties of Additively Manufactured and Conventional Maraging Steel

2020 ◽  
Vol 405 ◽  
pp. 133-138
Author(s):  
Ludmila Kučerová ◽  
Andrea Jandová ◽  
Ivana Zetková
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Precipitation Hardening ◽  
High Strength ◽  
Hardness Measurement ◽  
Nickel Steel ◽  
Heat Treated ◽  
Good Material ◽  
Iron Nickel

Maraging steel is an iron-nickel steel alloy, which achieves very good material properties like high toughness, hardness, good weldability, high strength and dimensional stability during heat treatment. In this work, maraging steel 18Ni-300 was manufactured by selective laser melting. It is a method of additive manufacturing (AM) technology, which produces prototypes and functional parts. Sample of additively manufactured and conventional steel with the same chemical composition were tested after in three different states – heat treated (as-built/as-received), solution annealed and precipitation hardened. Resulting microstructures were analysed by light and scanning electron microscopy and mechanical properties were obtained by hardness measurement and tensile test. Cellular martensitic microstructures were observed in additively manufactured samples and conventional maraging steel consisted of lath martensitic microstructures. Very similar mechanical properties were obtained for both steels after the application of the same heat treatment. Ultimate tensile strengths reached 839 – 900 MPa for samples without heat treatment and heat treated by solution annealing, the samples after precipitation hardening had tensile strengths of 1577 – 1711 MPa.

Improving Mechanical Properties of Twin-Roll Cast AZ31 by Wire Rolling

2021 ◽  
Vol 1016 ◽  
pp. 957-963
Author(s):  
Marie Moses ◽  
Madlen Ullmann ◽  
Rudolf Kawalla ◽  
Ulrich Prahl
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rolling Texture ◽  
Total Elongation ◽  
Roll Casting ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
Set Up ◽  
Twin Roll Cast ◽  
Twin Roll

Since 2018, the institute of metal forming has been studying the novel twin-roll casting (TRC) of magnesium wire at the pilot research plant set up specifically for this purpose. Light microscopic and scanning electronic investigations were carried out within this work and show the unique microstructure of twin-roll cast AZ31 magnesium alloy with grain sizes of about 10 μm ± 4 μm in centre and 39 μm ± 26 μm near the surface of the sample. By means of a short heat treatment (460 °C/15 min), segregations can be dissolved and grain size changes in centre to 19 μm ± 12 μm (increase) and near the surface to 12 μm ± 7 μm (decrease). Further, the mechanical properties of the twin-roll cast and heat-treated wire were analysed by tensile testing at room temperature. By heat treatment, the total elongation could be increased by a third whereas the strength decreases slightly. In heat-treated state, no preferred orientation is evident. In addition to the twin-roll cast and the heat-treated condition, the rolled state was analysed. For this purpose, the twin-roll cast wire was hot rolled using an oval-square calibration. After hot rolling, a dynamic recrystallization and grain refinement of the twin-roll cast wire could be achieved. It can be seen, that an increase in strength as well as in total elongation occur after wire rolling. Beside this, a rolling texture is evident.

Failure analysis of heat treated HSLA wheel bolt steels

2010 ◽  
Vol 6 (3) ◽  
pp. 373-382
Author(s):  
Ali Nazari ◽  
Shadi Riahi
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Failure Analysis ◽  
Heat Treating ◽  
Boron Steel ◽  
Content Type ◽  
Heat Treated ◽  
Before And After ◽  
Molybdenum Steel ◽  
Optimum Heat

PurposeThe aims of this study is to analyze failure of two types of high‐strength low‐alloy (HSLA) steels which are used in wheel bolts 10.9 grade, boron steel and chromium‐molybdenum steel, before and after heat treatment.Design/methodology/approachThe optimum heat treatment to obtain the best tensile behavior was determined and Charpy impact and Rockwell hardness tests were performed on the two steel types before and after the optimum heat treating.FindingsFractographic studies show a ductile fracture for heat‐treated boron steel while indicate a semi‐brittle fracture for heat‐treated chromium‐molybdenum steel. Formation of a small boron carbide amount during heat treating of boron steel results in increment the bolt's tensile strength while the ductility did not changed significantly. In the other hand, formation of chromium and molybdenum carbides during heat treating of chromium‐molybdenum steel increased the bolt's tensile strength with a considerable reduction in the final ductility.Originality/valueThis paper evaluates failure analysis of HSLA wheel bolt steels and compares their microstructure before and after the loading regime.

scholarly journals Study on the Properties of Transparent Bamboo Prepared by Epoxy Resin Impregnation

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 863 ◽  
Author(s):  
Yan Wu ◽  
Yajing Wang ◽  
Feng Yang ◽  
Jing Wang ◽  
Xuehua Wang
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Visible Light ◽  
Epoxy Resin ◽  
Raw Materials ◽  
Light Transmittance ◽  
Advantages And Disadvantages ◽  
Heat Treated ◽  
Before And After ◽  
Different Parts

In this paper, Moso bamboo (Phyllostachys heterocycle) before and after heat treatment were used as raw materials to prepare transparent bamboo (TB). In an acidic environment, the lignin contained in the bamboo material was removed to obtain a bamboo template, and an epoxy resin similar to the cellulose refractive index was used for vacuum impregnation into the bamboo template to obtain a transparent bamboo material. The purpose of this study was to compare the physical and chemical properties of TB and original bamboo and the differences between TBs before and after heat treatment, taken from different parts of bamboo, in order to explore the performance advantages and disadvantages of TB as a new material. The Fourier transform infrared spectroscopy analysis (FTIR), scanning electron microscope testing (SEM), three elements analysis, light transmittance testing, and mechanical strength testing were used to study the molecular composition, microstructure, chemical composition, light transmittance, and tensile strength of the TB samples. The results showed that the lignin content of the delignified bamboo templates was greatly reduced. In addition, the SEM images showed that a large amount of epoxy resin (type E51 and type B210 curing agent) was covered on the cross-section surface and pores of the TB samples. The FTIR showed that the epoxy molecular groups appeared on the TB, and the delignified bamboo template and the resin had a good synergy effect. According to the light transmittance testing, the original bamboo samples hardly contained light transmittance under visible light. The transmittance of transparent inner bamboo (TIB) and transparent heat-treated inner bamboo (THIB) could reach about 11%, and the transmittance of transparent outer bamboo (TOB) and transparent heat-treated outer bamboo (THOB) was about 2%. The light transmittance had been significantly improved when compared with the original bamboo samples. The transmittances of the TB samples before and after heat treatment in different parts of bamboo were different. In the visible light irradiation range, the light transmittances of TB samples were as follows: TIB > THIB and THOB > TOB. Meanwhile, the tensile strength of TB was reduced, especially for TOB and THOB. In addition, TB has a wide range of raw materials, and the preparation process is environmentally friendly. It can be used for decorative materials in homes, buildings, etc., and has a great application potential.

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