Lath martensite in 1.4%C ultra-high carbon steel and its grain size effect

2004 ◽  
Vol 385 (1-2) ◽  
pp. 440-444 ◽  
Author(s):  
Z JIEWU ◽  
X YAN ◽  
Y LIU
2005 ◽  
Vol 297-300 ◽  
pp. 1178-1182
Author(s):  
Yong Ning Liu ◽  
Jie Wu Zhu ◽  
Yan Xu

1.4 %C ultra high carbon steel (UHCS) was prepared in order to study the structure of martensite transformation and mechanical properties. Ultra-fine spherical carbide and ultra-fine austenite grain size were obtained. A great deal of lath martensite was observed after quenching. The phenomenon does not agree with the traditional knowledge that the lath martensite would disappear when carbon content is in excess of 0.8% in austenite. The strength, fatigue properties and fracture toughness have been measured. A good combination of strength, toughness and fatigue properties come from fine and uniform distributed carbide particles and ultra-fine austenite grain size. Fracture strength increases by 48%, yield strength increases by 15% and plasticity keep the same comparing with that of hardened and tempered 40CrNiMo. The carbon content of ultrahigh carbon steels (UHCS) is in the range of 1.0-2.1% [1, 2]. Traditional heat treatments for normal steels will cause the microstructure of UHCS to be coarse and do not produce optimal properties. With controlled rolling and special heat treatment, UHCS can be in ferrite, pearlite, bainnite or martensite structures, which all have different mechanical properties. The yield stress of a 1.8%C, 1.6%Al ferrite UHCS can reach 1500MPa, which is much higher than that of high strength and plain alloy steels [3]. The tensile strength of a 1.25%C-1.5%Cr pearlite UHCS can reach 1810Mpa and its elongation can be 18%. When it is treated into martensite, its compression strength reached to 4690Mpa and compression strain reached to 26% [1, 4], which is comparable to WC-12Co. Such good mechanical properties can be ascribed to the ultra fine grain sizes because of the undissolved carbide particles which resist growth of austenite grain during heating. Another reason could be the lath martensite structures. O.D.Sherby [4] had reported that there was a lot of lath martensite in quenched UHCS. The UHCS was considered not only as tool steels but also as good structure materials. Fracture and fatigue properties are important for structure materials. However, they have rarely been studied. The present paper is going to study the martensite structure and mechanical properties of a prepared 1.4% C UHCS.


2021 ◽  
Vol 1 (1) ◽  
pp. 51
Author(s):  
Alfan Ekajati Latief ◽  
Syahril Sayuti ◽  
Rakean Wide Windujati

 ABSTRAKTanto merupakan senjata tajam yang berasal dari Jepang dan merupakan senjata kedua bagi para Samurai di Jepang. Tanto biasa terbuat dari baja karbon menengah hingga baja karbon tinggi yang. Material baja yang digunakan untuk pembuatan Tanto dalam penelitian ini adalah baja AISI seri O1 karena memiliki karakteristik sifat mampu bentuk yang baik serat dapat dikuatkan melalui proses heat treatment. Material baja ini dibuat dengan proses tempa lipat  dengan variasi tempa empat lipatan dan satu lipatan. Pembuatan Tanto dan spesimen uji dilakukan dengan proses tempa lipat secara konvensional menggunakan tungku arang, dengan temperatur tempa rata-rata yaitu ±1200oC, kemudian dilanjutkan dengan quenching pada temperatur ± 850oC, serta tempering pada temperatur ±250oC. Penelitian ditujukan untuk mengetahui pengaruh dari proses tempa empat lipatan dan tempa satu lipatan terhadap sifat mekanik, yaitu kekerasan dan kekuatan impak serta untuk melihat perubahan pada struktur mikro. Hasil pengujian menunjukkan bahwa nilai kekerasan paling tinggi sebesar41HRC yang dimiliki oleh pada raw material, ,sedangkan nilai impak paling tinggi sebesar 224,02 Joule/cm² ayng dicapai oleh material dengan proses tempa empat lipatan, Fasa akhir yang ditemukan pada baja tempa empat lipatan adalah  bainit dan martensit, sementara  perlit dan ferit ditemukan  pada baja satu lipatan, dan lath martensit ditemukan pada pada raw material  Kata kunci: Pisau Tanto, Tempa lipat ,Quenching, Tempering, Uji Impak  ABSTRACT Tanto is a sharp weapon originating  from Japan and is the second weapon for Samurai in Japan. Tanto is usually made of medium carbon steel to high carbon steel. The material which is used in this research is AISI O1 series steel because of its high ability to be formed and also can be made tough through a heat treatment process. This steel is made by folding forge process, with variation in number of folding, which is 4 folds and 1 fold. The making of Tanto and test specimens was carried out by conventional fold forging processes by using a charcoal furnace, with an average forging temperature at ± 1200oC, continue with quenching at ± 850oC, and tempering at ± 250oC. The research is carried out in order to determine the effect of the four-folds forging and one-fold forging to the mechanical behavior, which are hardness and impact strength,  and also to see change in its micro structure. The test that have been carried out shows that the highest hardness value of 41 HRC owned by raw material, while the highest impact value of 224.02 Joules / cm² obtained by material with four layer forging process. Final phases that found in the four-fold forged steel are bainite and martensite, pearlite and ferrite found in one-fold forged steel. and lath martensite in found in the raw material. Keywords: Tanto Knife, Folding Forging, Quenching, Tempering, Testing, Impact Tests


2020 ◽  
Vol 363 ◽  
pp. 652-656
Author(s):  
Tao Jiang ◽  
Junjie Sun ◽  
Yingjun Wang ◽  
Hongji Liu ◽  
Shengwu Guo ◽  
...  

2014 ◽  
Vol 922 ◽  
pp. 183-188
Author(s):  
Xing Jian Gao ◽  
Zheng Yi Jiang ◽  
Dong Bin Wei ◽  
Hui Jun Li ◽  
Si Hai Jiao ◽  
...  

A high carbon steel (HCS) and low carbon steel (LCS) bimetal was fabricated by centrifugal composite casting. Two different thermomechanical treatments (TMT1 and TMT2) were employed to improve the mechanical properties of the bimetal. TMT1 process includes 60% of overall reduction by hot compression with temperatures of 1100 and 800oC, respectively. While TMT2 process involves 60% of overall reduction using the two-step deformation method, which is a combination of non-isothermal compression cooling from 1100 to 800oC and isothermal compression at 800oC. The flow stress behavior, microstructural evolution and microhardness variation were analysed. Experimental results show that both TMT processes contributed to the improvement in mechanical properties resulting from a refinement of the grain size and an increase of density of pearlitic lamella in HCS layer. However, TMT2 process gave a better efficiency and a more significance in improvement of properties with the evidence of the same overall reduction leading to a higher microhardness.


2001 ◽  
Vol 81 (12) ◽  
pp. 2797-2808
Author(s):  
Rustem Bagramov, Daniele Mari, Willy Benoi

2019 ◽  
Vol 2019 (3) ◽  
pp. 29-37
Author(s):  
A.A. Polishko ◽  
◽  
L.B. Medovar ◽  
A.P. Stovpchenko ◽  
E.V. Antipin ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document