Short-time heat treatment of press hardened steel for laser assisted clinching

2014 ◽  
Vol 30 (11) ◽  
pp. 1287-1296 ◽  
Author(s):  
M. Reich ◽  
J. Osten ◽  
B. Milkereit ◽  
J. Kalich ◽  
U. Füssel ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hardened Steel ◽  
Short Time

Softening of High-Strength Steel for Laser Assisted Clinching

2014 ◽  
Vol 966-967 ◽  
pp. 617-627 ◽  
Author(s):  
Julia Osten ◽  
Paul Söllig ◽  
Michael Reich ◽  
Jan Kalich ◽  
Uwe Füssel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Laser Heating ◽  
High Strength Steels ◽  
High Strength ◽  
Mechanical Analysis ◽  
Hardened Steel ◽  
The Press ◽  
Short Time ◽  
First Time

The conventional clinching of steels is currently limited to tensile strength less than 800 N/mm2 and to elongation at fracture more than 14 %. To realise the clinching of high-strength steels, the sheet can be heated locally at the joint, to improve ductility. Thereby the material characteristics outside the joint should be maintained. This could be achieved by means of short-time laser heating. The short-time tempering behaviour of press hardened steel 22MnB5 has been analysed. The mechanical properties during a short-time heat treatment were investigated by thermo-mechanical analysis in a deformation dilatometer. Thereby laser-assisted clinching shall be established and an efficient form-closed and force-closed connection shall be produced. As a result, the press hardened steel 22MnB5 could be clinched by laser assistance for the very first time.

Effect of a Complex Heat Treatment on the Structure of 300M Steel

1981 ◽  
Vol 39 ◽  
pp. 312-313
Author(s):  
R. Padmanabhan ◽  
W. E. Wood
Keyword(s):  
Heat Treatment ◽  
Metal Carbides ◽  
Austenite Grain Size ◽  
300M Steel ◽  
Heat Treated ◽  
Strain Fracture ◽  
Prior Austenite Grain Size ◽  
Short Time ◽  
Final Tempering ◽  
Similar Yield

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.

Evaluation of S-N curves including failure probabilities using short-time procedures

2021 ◽  
Vol 63 (8) ◽  
pp. 705-713
Author(s):  
Ruth Acosta ◽  
Christian Boller ◽  
Markus Doktor ◽  
Haoran Wu ◽  
Hanna Jost ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Treatment ◽  
Fatigue Life ◽  
Statistical Evaluation ◽  
Field Measurements ◽  
Treatment Conditions ◽  
Evaluation Strategies ◽  
Magnetic Field Measurements ◽  
Short Time ◽  
Experimental Effort

Abstract In recent years, different short-time procedures have been developed that significantly reduce the experimental effort required to generate S-N curves and thus S-N databases. Methods like StressLife, StrainLife, and SteBLife are some of those which have shown enormous potential in this respect. In this contribution, the practicability of the SteBLife method is shown. Two S-N curve evaluation strategies based on temperature and magnetic field measurements are presented. These take statistical evaluation into account, describing a material’s scatter in terms of fatigue life. In order to demonstrate the versatility of the approach and to underline the advantages in terms of effort saved when compared to conventional procedures, the process on how to get the required information obtained is shown for three unalloyed and low-alloyed steels under different heat treatment conditions.

Retrogression and Re-aging Heat Treatment: AA7XXX Aluminum Alloys

2019 ◽  
Author(s):  
V. Anil Kumar ◽  
S. Arjun ◽  
R.K. Gupta ◽  
P.V. Venkitakrishnan
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Industrial Applications ◽  
Age Hardening ◽  
Large Cross Section ◽  
Structural Applications ◽  
The Matrix ◽  
Peak Aged ◽  
Aged Temper ◽  
Short Time

Retrogression and re-aging (RRA) treatment was introduced to increase the stress corrosion cracking (SCC) resistance while retaining the strength attainable in T6 (peak aged) temper. Retrogression is a short-term heat treatment at an elevated temperature wherein a partial dissolution of metastable precipitates occurs, which are responsible for the hardening. During the next step, the material is re-aged in the regime of typical age hardening parameters to restore the strength with improved ductility. Response of RRA treatment has been reported on AA7XXX series Aluminum alloys such as AA7075, AA7050, AA7150, AA7049, and AA7010. Studies have been done on the effect of RRA on microstructure, mechanical properties such as tensile and hardness, corrosion, exfoliation corrosion, and SCC resistance by various researchers. The key characteristic of RRA is retrogression, which makes the re-precipitation in the matrix and coarsening of grain boundary precipitates such as MgZn2, η′. The retrogression treatment however requires high temperature and a short time, which limits the industrial application of RRA, especially in the heat treatment of the components with large cross section, due to the inherent thermal conductivity limitations. Hence, further work needs to be done in this area to apply this specialized heat treatment for industrial applications. This article brings out a comprehension of the changes in microstructure, tensile properties, and corrosion resistance of the various commonly used AA7XXX Aluminum alloys in structural applications with RRA heat treatment. The future scope of the work in RRA heat treatment is also discussed in this article.

scholarly journals Designing a Quick Fix Shutter for Auto-Disinfecting Scan Glass Surface in Biometric Scanners

2020 ◽  
Author(s):  
Deepalekshmi Ponnamma ◽  
Mohammad Talal Houkan ◽  
Muni Raj Mourya ◽  
Noora Al-Thani
Keyword(s):  
Infectious Disease ◽  
Heat Treatment ◽  
Glass Surface ◽  
Universal Design ◽  
Professional Life ◽  
Cross Contamination ◽  
Finger Print ◽  
Potential Sources ◽  
Single Use ◽  
Short Time

Fingerprint scanners are significant devices in professional life, and its contamination can be potential sources of COVID-19 transmission. Manual disinfection of the fingerprint scanner after every single use is time consuming and even can adversely affect its electronics/functioning. Thus, with an aim to prevent the spread of infectious disease by cross contamination and implement the safe use of fingerprint scanner, we have developed a smart quick fix technology for automatic disinfection of finger print scanner glass after every single use. The smart portable top mount assembly uses two different disinfecting methods that ensures higher degree of disinfection. The disinfection is based on the simultaneous ultraviolet (UV) and heat treatment for a specific short time, and required to kill all the viruses on the scan glass surface. Moreover, developing this disinfecting technology with a universal design that can be fitted to any finger print scanner irrespective to its size makes it a novel idea.

scholarly journals Effect of Heat Treatment on Rheological Properties of Bambangan (Mangifera pajang kosterm) Fruit Juice

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Jumardi Roslan ◽  
Hay Chye Ling ◽  
Mohd Dona Sintang ◽  
Suryani Saallah
Keyword(s):  
Heat Treatment ◽  
Rheological Properties ◽  
Fruit Juice ◽  
Market Potential ◽  
Pseudoplastic Fluid ◽  
Treatment Conditions ◽  
High Temperature Short Time ◽  
Long Time ◽  
Mild Temperature ◽  
Short Time

Bambangan (Mangifera pajang Kosterm) is an indigenous fruit that can be found in Borneo Island including Sabah and Sarawak (Malaysia), Kalimantan (Indonesia), and Brunei. Besides being freshly eaten, the pulp of bambangan fruit can be processed for juice production to expand its market potential. During the processing of fruit juice, the application of heat treatment such as pasteurization and sterilization might influence their rheological behavior. Thus, the present study aims to investigate the effect of heat treatment on the rheological properties of bambangan fruit juice (BFJ). The freshly squeezed BFJ was subjected to different heat treatment conditions; sterilization (121°C, 3 minutes), mild temperature long time (MTLT) pasteurization (65°C, 15 minutes), and high temperature short time (HTST) pasteurization (90°C, 1 minute). Rheological analysis of the heat-treated BFJ was performed using a rheometer at a shear rate ranging from 1 to 250 s-1 and a temperature between 5 °C to 70 °C. Pasteurization at 90 °C for 1 minute (HTST) was found to be the most suitable heat treatment for the BFJ. At this condition, the BFJ exhibited a non-Newtonian pseudoplastic fluid behavior (n < 1), fitted well with the Herschel-Bulkey model. The value of parameters obtained from Herschel-Bulkley equation for HTST treatment of bambangan juice were n= 0.83, k= 0.32 and yield stress= 3.96. The viscosity values of HTST bambangan juice at the temperature of 5, 20, 40 and 70 °C were 3.53, 2.33, 1.53 and 1.76 Pa.s respectively. This rheological information is of fundamental importance in optimizing equipment design, process control, and sensory evaluation.

scholarly journals Investigation of a partial, inductive short-time heat treatment of thin metal sheets integrated into the forming process

2018 ◽  
Vol 190 ◽  
pp. 12008
Author(s):  
Benjamin Clausius ◽  
Petra Maier
Keyword(s):  
Heat Treatment ◽  
Strain Hardening ◽  
Sheet Thickness ◽  
Local Strain ◽  
Single Step ◽  
Thin Metal ◽  
Recrystallization Annealing ◽  
Forming Process ◽  
Metal Sheets ◽  
Short Time

Flanging is a widespread method in the sheet metal working industry to connect same or different materials by forming. Especially the sealing technology makes high demands on the flanging process: a low sheet thickness of the inner eyelet is necessary for proper sealing. The outer edges of the neck rings are mostly manufactured by shear cutting. The quality of the cut surface and the level of the local strain hardening influence decisively the limit of the flanging process by possible cracking. This paper is focused on the dependencies of these factors regarding thin metal sheets of different materials with a thickness down to 100 μm. It could be shown that strain hardening has a stronger effect on the process limits compared to the notch effect of the sheet edges when using standard values for the clearance of the shear cutting tool. Furthermore, a process is investigated with a partial inductive short-time heat treatment of the most deformed edge area. Due to the low thickness of the material and low heat capacities related thereto, it is possible to integrate a recrystallization annealing as single step into the forming process. As a result, the strain hardening can be removed from the affected zone directly between two forming steps to increase the process limits.

scholarly journals Effects of a Short Heat Treatment Period on the Pullout Resistance of Shape Memory Alloy Fibers in Mortar

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2278 ◽  
Author(s):  
Min Kyoung Kim ◽  
Dong Joo Kim ◽  
Young-Soo Chung ◽  
Eunsoo Choi
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Memory Effects ◽  
Stress Recovery ◽  
Pullout Resistance ◽  
Pullout Tests ◽  
Dog Bone ◽  
Shape Memory Effects ◽  
Short Time

The feasibility of the crack closure of cementitious composites reinforced with shape memory alloy (SMA) fibers was investigated by performing single-fiber pullout tests. To demonstrate the fast crack closing ability, in this study, a heat treatment (300 °C) was applied for a short time (10 min). A short heat treatment was applied for 10 min, after the slip reached 0.5 mm, to activate the shape memory effects of cold-drawn SMA fibers. Two types of alloys were investigated, NiTi and NiTiNb, with two geometries, either smooth or dog-bone-shaped. During the heat treatment, the pullout stress of the SMA fibers initially decreased due to thermal extension, and then increased after heating for 1–3 min, resulting from the shape memory effects. However, their pullout stress recovery during and after the heat treatment was different for the different alloys and fiber geometries. The NiTi fibers generally produced a higher and faster recovery in terms of their pullout stress than the NiTiNb fibers, while the dog-bone-shaped fibers showed a faster pullout stress recovery than the smooth fibers.

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