VHCF Strength of Helical Compression Springs - Influence of Heat Treatment Temperature before Shot Peening

2015 ◽  
Vol 664 ◽  
pp. 140-149
Author(s):  
Isabell Brunner ◽  
Desislava Veleva ◽  
Jörg Beyer ◽  
Matthias Oechsner
Keyword(s):  
Heat Treatment ◽  
Crack Initiation ◽  
Shot Peening ◽  
Heat Treatment Temperature ◽  
Fracture Behaviour ◽  
Steel Wire ◽  
Fatigue Tests ◽  
Treatment Temperature ◽  
Spring Steel ◽  
Compression Springs

Previous fatigue tests show that the heat treatment temperature has a significant influence on high cycle fatigue behaviour of helical compression springs. In order to investigate the effect of the heat treatment temperature on the fracture behaviour and the cyclic life, fatigue tests in the very high cycle regime (VHCF) were conducted.The tested springs were manufactured from oil hardened and tempered SiCr-alloyed valve spring steel wire with a diameter of d = 1.6 mm. After winding and grinding of the spring endings, the springs were heat treated at either 360°C or 400°C for 30 minutes. In order to generate compressive residual stresses in the surface area, the springs were shot peened. After shot peening, the springs were again annealed at 240°C for 30 minutes.Fatigue tests were conducted at 40 Hz using a special spring fatigue device. Up to 900 springs were tested simultaneously at various stress levels to 5∙108or 109cycles. Fractured springs were investigated by means of a stereomicroscope as well as a scanning electron microscope to analyse the fracture behaviour and failure mechanisms. The vast majority of the springs show crack initiation at the surface at the inner side of the coil. Less frequently, crack initiation occurs at subsurface locations. Our results show that heat treatment at a temperature of 360°C leads to four times more subsurface cracks than at a temperature of 400°C and reduces the overall fatigue life time.

scholarly journals On the effects of heat and surface treatment on the fatigue performance of high-strength leaf springs

2021 ◽  
Vol 349 ◽  
pp. 04007
Author(s):  
Michail Malikoutsakis ◽  
Christos Gakias ◽  
Ioannis Makris ◽  
Peter Kinzel ◽  
Eckehard Müller ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Applied Stress ◽  
Shot Peening ◽  
High Strength ◽  
Fatigue Tests ◽  
Spring Steel ◽  
Fatigue Performance ◽  
Leaf Springs ◽  
Before And After ◽  
Stress Ratios

Leaf springs constitute the most effective suspension way of commercial vehicle axles from the cost and maintainability point of view. Especially in case of front axles, they overtake both the guidance and suspension functions, which consequently designates them as safety components, whose pre-mature failure is explicitly prohibited. The present paper deals with the fatigue performance of downsized parabolic leaf specimens made of the high-strength spring steel 51CrV4 under serial manufacturing conditions. It focuses on the influence of the major manufacturing steps, i.e. the heat treatment and the subsequently applied stress shot peening. The effectiveness of the applied heat treatment on the microstructure transformation and the extent of surface decarburization is determined by means of optical microscopy and corresponding microstructural analyses. Comprehensive series of constant amplitude fatigue tests are executed before and after the applied stress shot peening to quantify its effectiveness on the fatigue performance. The tests cover two characteristic stress ratios of operational significance with the complete range of interest being experimentally investigated. Additionally, surface residual stresses measurements together with micro- and macro-hardness and roughness values before and after stress shot peening are executed to expose the influence of each individual technological effect on the overall fatigue performance.

scholarly journals Heat Treatment of Cold Formed Springs Made from Oil Hardened and Tempered Spring Steel Wire

2017 ◽  
Vol 892 ◽  
pp. 16-20
Author(s):  
Veronika Geinitz ◽  
Ulf Kletzin
Keyword(s):  
Heat Treatment ◽  
Mechanical Characteristics ◽  
Steel Wire ◽  
Spring Steel ◽  
Treatment Technology ◽  
Cold Forming ◽  
Steel Wires ◽  
Heat Treatment Technology ◽  
Compression Springs

The heat treatment after cold forming is used to decrease the residual stresses of springs, but the mechanical characteristics of the spring steel wires alters, too. This presentation describes the influence of the heat treatment technology (oven equipment, temperature, duration,…) to the properties and quality of helical compression springs made from oil hardened and tempered spring steel wire.

Effects of Heat Treatment Temperature on Photocatalytic Activity of TiO2/SiO2 Composite Aerogels

2013 ◽  
Vol 27 (10) ◽  
pp. 1079-1083
Author(s):  
Zhao-Hui LIU ◽  
Gen-Liang HOU ◽  
Xun-Jia SU ◽  
Feng GUO ◽  
Zhou XIAO ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Composite Aerogels

Spin-dependent-magnetoresistance control by regulation of heat treatment temperature for magnetite nano-particle sinter

2009 ◽  
Vol 18 (12) ◽  
pp. 935-938
Author(s):  
H. Kobori ◽  
T. Asahi ◽  
Y. Yamasaki ◽  
A. Sugimura ◽  
T. Taniguchi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Nano Particle

scholarly journals Water Resistance and Creep Behavior of Heat-Treated Moso Bamboo Determined by the Stepped Isostress Method

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1264
Author(s):  
Teng-Chun Yang ◽  
Tung-Lin Wu ◽  
Chin-Hao Yeh
Keyword(s):  
Heat Treatment ◽  
Water Absorption ◽  
Creep Behavior ◽  
Heat Treatment Temperature ◽  
Water Resistance ◽  
Absorption Efficiency ◽  
Treatment Temperature ◽  
Moso Bamboo ◽  
Phyllostachys Pubescens ◽  
Heat Treated

The influence of heat treatment on the physico-mechanical properties, water resistance, and creep behavior of moso bamboo (Phyllostachys pubescens) was determined in this study. The results revealed that the density, moisture content, and flexural properties showed negative relationships with the heat treatment temperature, while an improvement in the dimensional stability (anti-swelling efficiency and anti-water absorption efficiency) of heat-treated samples was observed during water absorption tests. Additionally, the creep master curves of the untreated and heat-treated samples were successfully constructed using the stepped isostress method (SSM) at a series of elevated stresses. Furthermore, the SSM-predicted creep compliance curves fit well with the 90-day full-scale experimental data. When the heat treatment temperature increased to 180 °C, the degradation ratio of the creep resistance (rd) significantly increased over all periods. However, the rd of the tested bamboo decreased as the heat treatment temperature increased up to 220 °C.

Effect of Heat Treatment on the Microstructure and Property of TiAl Alloys Prepared by Gas Atomization Powders

2013 ◽  
Vol 747-748 ◽  
pp. 497-501
Author(s):  
Na Liu ◽  
Zhou Li ◽  
Guo Qing Zhang ◽  
Hua Yuan ◽  
Wen Yong Xu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Tial Alloy ◽  
Lamellar Microstructure ◽  
Treatment Temperature ◽  
Gas Atomization ◽  
Thermally Induced ◽  
Heat Treated ◽  
Fine Duplex ◽  
Step Heat Treatment

Powder metallurgical TiAl alloy was fabricated by gas atomization powders, and the effect of heat treatment temperature on the microstructure evolution and room tensile properties of PM TiAl alloy was investigated. The uniform fine duplex microstructure was formed in PM TiAl based alloy after being heat treated at 1250/2h followed by furnace cooling (FC)+ 900/6h (FC). When the first step heat treatment temperature was improved to 1360/1h, the near lamellar microstructure was achieved. The ductility of the alloy after heat treatment improved markedly to 1.2% and 0.6%, but the tensile strength decreased to 570MPa and 600MPa compared to 655MPa of as-HIP TiAl alloy. Post heat treatment at the higher temperature in the alpha plus gamma field would regenerate thermally induced porosity (TIP).

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