Characteristics of Heat Treatment on Different Materials during Laser Surface Hardening of Cast Iron for Die

2011 ◽  
Vol 35 (12) ◽  
pp. 1663-1668
Author(s):  
Jong-Do Kim ◽  
Moo-Keun Song ◽  
Hyun-Tae Hwang
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Surface Hardening ◽  
Laser Surface ◽  
Laser Surface Hardening

scholarly journals Comparison of Wear Performance of Austempered and Quench-Tempered Gray Cast Irons Enhanced by Laser Hardening Treatment

2020 ◽  
Vol 10 (9) ◽  
pp. 3049
Author(s):  
Bingxu Wang ◽  
Gary C. Barber ◽  
Rui Wang ◽  
Yuming Pan
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Surface Hardening ◽  
Gray Cast Iron ◽  
High Hardness ◽  
Laser Surface ◽  
Gray Cast ◽  
Wear Loss ◽  
Laser Surface Hardening ◽  
Hardening Treatment

The current research studied the effects of laser surface hardening treatment on the phase transformation and wear properties of gray cast irons heat treated by austempering or quench-tempering, respectively. Three austempering temperatures of 232 °C, 288 °C, and 343 °C with a constant holding duration of 120 min and three tempering temperatures of 316 °C, 399 °C, and 482 °C with a constant holding duration of 60 min were utilized to prepare austempered and quench-tempered gray cast iron specimens with equivalent macro-hardness values. A ball-on-flat reciprocating wear test configuration was used to investigate the wear resistance of austempered and quench-tempered gray cast iron specimens before and after applying laser surface-hardening treatment. The phase transformation, hardness, mass loss, and worn surfaces were evaluated. There were four zones in the matrix of the laser-hardened austempered gray cast iron. Zone 1 contained ledeburite without the presence of graphite flakes. Zone 2 contained martensite and had a high hardness, which was greater than 67 HRC. Zone 4 was the substrate containing the acicular ferrite and carbon-saturated austenite with a hardness of 41–27 HRC. In Zone 3, the substrate was tempered by the low thermal radiation. For the laser-hardened quench-tempered gray cast iron specimens, three zones were observed beneath the laser-hardened surface. Zone 1 also contained ledeburite, and Zone 2 was full martensite. Zone 3 was the substrate containing the tempered martensite. The tempered martensite became coarse with increasing tempering temperature due to the decomposition of the as-quenched martensite and precipitation of cementite particles. In the wear tests, the gray cast iron specimens without heat treatment had the highest wear loss. The wear performance was improved by applying quench-tempering heat treatment and further enhanced by applying austempering heat treatment. Austempered gray cast iron specimens had lower mass loss than the quench-tempered gray cast iron specimens, which was attributed to the high fracture toughness of acicular ferrite and stable austenite. After utilizing the laser surface hardening treatment, both austempered and quench-tempered gray cast iron specimens had decreased wear loss due to the high surface protection provided by the ledeburitic and martensitic structures with high hardness. In the worn surfaces, it was found that cracks were the dominant wear mechanism. The results of this work have significant value in the future applications of gray cast iron engineering components and provide valuable references for future studies on laser-hardened gray cast iron.

Laser Surface Hardening of Gray Cast Iron Used for Piston Ring

2002 ◽  
Vol 11 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Jong-Hyun Hwang ◽  
Yun-Sig Lee ◽  
Dae-Young Kim ◽  
Joong-Geun Youn
Keyword(s):  
Cast Iron ◽  
Surface Hardening ◽  
Piston Ring ◽  
Gray Cast Iron ◽  
Laser Surface ◽  
Gray Cast ◽  
Laser Surface Hardening

scholarly journals Laser Surface Hardening of Ni-hard White Cast Iron

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 795
Author(s):  
Samar Reda Al-Sayed ◽  
Ahmed Magdi Elshazli ◽  
Abdel Hamid Ahmed Hussein
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Impact Toughness ◽  
Surface Hardening ◽  
White Cast Iron ◽  
Laser Surface ◽  
Hard Alloys ◽  
The Core ◽  
Laser Surface Hardening ◽  
The Impact

Laser surface treatment on two different types of nickel–chromium white cast iron (Ni-hard) alloys (Ni-hard 1 and Ni-hard 4) was investigated. Nd:YAG laser of 2.2-kw with continuous wave was used. Ni-hard alloys are promising engineering materials, which are extensively used in applications where good resistance to abrasion wear is essential. The conventional hardening of such alloys leads to high wear resistance nevertheless, the core of the alloy suffers from low toughness. Therefore, it would be beneficial to harden the surface via laser surface technology which keeps the core tough enough to resist high impact shocks. A laser power of different levels (600, 800 and 1000 Watts) corresponding to three different laser scanning speeds (3, 4 and 5 m·min−1) was adopted hoping to reach optimum conditions for wear resistance and impact toughness. The optimum condition for both properties was recorded at heat input of 16.78 J·mm−2. The present findings reflect that the microhardness values and wear resistance clearly increased after laser hardening by almost three times due to laser surface hardening, whereas, the impact toughness was increased from five joules obtained from conventionally heat-treated samples to 6.4 J as gained from laser-treated samples.

Effects of CO2 Laser Surface Hardening in the Unlubricated Wear of Ductile Cast Iron Against Alumina

1996 ◽  
Vol 118 (4) ◽  
pp. 748-752 ◽  
Author(s):  
C. Papaphilippou ◽  
M. Vardavoulias ◽  
M. Jeandin
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Co2 Laser ◽  
Surface Hardening ◽  
Normal Load ◽  
Ductile Cast Iron ◽  
Laser Surface ◽  
Sliding Velocity ◽  
Wear Coefficient ◽  
Laser Surface Hardening

The microstructure of a ferrito-pearlitic ductile cast iron has been modified by CO2 laser surface hardening. Analysis of the laser-processed surfaces showed a dramatic increase in microhardness. Dry sliding wear of laser-treated specimens against an alumina counterbody has been investigated by “ball-on-disk” testing. The evolution of the wear coefficient, as well as metallographic observations, revealed an oxidational wear mechanism. The wear resistance of the laser-treated samples was significantly enhanced. The laser-treated cast iron has a better resistance to abrasion and plastic deformation. The improvement of the wear resistance was due to the fine and homogeneous microstructure produced after laser-treatment. Wear plots showing the evolution of wear coefficient with normal load, sliding velocity, and humidity have been established. The wear of the laser-treated cast iron is not influenced by the variation of operating conditions (normal load, sliding velocity, and relative humidity).

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