Microstructure of ausformed lath martensite in 18%Ni maraging steel

2003 ◽  
Vol 112 ◽  
pp. 453-456 ◽  
Author(s):  
S. Morito ◽  
I. Kishida ◽  
T. Maki
Keyword(s):  
Maraging Steel ◽  
Lath Martensite

Microstructure of resistance spot welding of maraging steels

1990 ◽  
Vol 48 (4) ◽  
pp. 900-901
Author(s):  
I. Neuman ◽  
S.F. Dirnfeld ◽  
I. Minkoff
Keyword(s):  
Maraging Steel ◽  
Spot Welding ◽  
Lath Martensite ◽  
Base Material ◽  
Aging Treatment ◽  
High Strength ◽  
Maraging Steels ◽  
Heat Treated ◽  
Current Cycle ◽  
Welding Processes

Experimental work on the spot welding of Maraging Steels revealed a surprisingly low level of strength - both in the as welded and in aged conditions. This appeared unusual since in the welding of these materials by other welding processes (TIG,MIG) the strength level is almost that of the base material. The maraging steel C250 investigated had the composition: 18wt%Ni, 8wt%Co, 5wt%Mo and additions of Al and Ti. It has a nominal tensile strength of 250 KSI. The heat treated structure of maraging steel is lath martensite the final high strength is reached by aging treatment at 485°C for 3-4 hours. During the aging process precipitation takes place of Ni3Mo and Ni3Ti and an ordered solid solution containing Co is formed.Three types of spot welding cycles were investigated: multi-pulse current cycle, bi-pulse cycle and single pulsle cycle. TIG welded samples were also tested for comparison.The microstructure investigations were carried out by SEM and EDS as well as by fractography. For multicycle spot welded maraging C250 (without aging), the dendrites start from the fusion line towards the nugget centre with an epitaxial growth region of various widths, as seen in Figure 1.

scholarly journals Evidence of Martensitic Transformation in Fe-Mn-Al Steel Similar to Maraging Steel

2020 ◽  
Vol 52 (1) ◽  
pp. 26-33
Author(s):  
Gurumayum Robert Kenedy ◽  
Yi-Jyun Lin ◽  
Wei-Chun Cheng
Keyword(s):  
Martensitic Transformation ◽  
Maraging Steel ◽  
Trip Steel ◽  
Single Phase ◽  
Lath Martensite ◽  
Al Alloy ◽  
Air Cooling ◽  
Small Temperature Gradient ◽  
Austenite Grains ◽  
Equilibrium Phases

AbstractThe Fe-Mn-Al steels claim a low density, and some fall into the category of transformation-induced plasticity (TRIP) steel. In Fe-Mn-Al TRIP steel development, phase transformations play an important role. Herein, the martensitic transformation of an Fe-16.7 Mn-3.4 Al ternary alloy (wt pct) was experimentally discovered, whose equilibrium phases are a single phase of austenite at 1373 K and dual phases of ferrite and austenite at low temperature. Ferritic lath martensite forms in the prior austenite grains after cooling from 1373 K under various cooling rates via quenching, air cooling, and furnace cooling. The formation mechanism of the ferritic lath martensite is different from that of traditional ferritic lath martensite in steel and quite similar to that in maraging steel. A slight strain energy coupled with a small temperature gradient can lead to the formation of ferritic lath martensite in the Fe-Mn-Al alloy after cooling from high temperature. It is also found that micro-twins exist in the ferritic lath martensite.

Three-Dimensional Approach to Observing Growth of Blocks and Packets in Fe-18Ni Maraging Steel

2014 ◽  
Vol 783-786 ◽  
pp. 916-919 ◽  
Author(s):  
Shigekazu Morito ◽  
Show Yoshida ◽  
Rei Hayamizu ◽  
Taisuke Hayashi ◽  
Takuya Ohba ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Grain Boundaries ◽  
Maraging Steel ◽  
Prior Austenite ◽  
Early Stage ◽  
Lath Martensite ◽  
Three Dimensional ◽  
Boundary Edge ◽  
Austenite Grain ◽  
Prior Austenite Grain

The present study aims to clarify the development of blocks and packets in lath martensite in Fe–18Ni maraging steel using three-dimensional observations. The specimens were step-quenched in order to clarify the sequential development of the three-dimensional morphology in a prior austenite grain. In a prior austenite grain, we found that five independent packets formed during the early stage of martensitic transformation. Four of the packets exist along the prior austenite grain boundaries and one packet grows from the boundary edge into the prior austenite grain. Each packet consists of a single block, although the fraction of martensitic transformation is 50.6%. The observed rules of the block-selection are as follows: (1) the blocks have near Kurdjumov–Sachs orientation relationship with adjacent austenite grains and elongated directions of the laths are parallel to adjacent grain boundaries and (2) transformation shear directions of the laths are parallel to adjacent grain boundaries.

Microstructure and crystallographic features of lath martensite in Fe10Cr10Ni2W maraging steel

1992 ◽  
Vol 156 (1) ◽  
pp. L1-L3
Author(s):  
Jin I. Suk ◽  
Soon H. Hong ◽  
Young G. Kim ◽  
Soo W. Nam
Keyword(s):  
Maraging Steel ◽  
Lath Martensite

Complex Characterization of a New Low Ni Maraging Steel with Enhance Service Stability

2012 ◽  
Vol 188 ◽  
pp. 346-351
Author(s):  
Mihai Branzei ◽  
Ion Nedelcu ◽  
Marian Miculescu
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Maraging Steel ◽  
Lath Martensite ◽  
Structure Stability ◽  
Treatment Technology ◽  
New Type ◽  
Optimum Heat ◽  
National Patent

A new low Ni maraging steel, based on 18Ni (300) type has been developed. The optimized chemical composition (complex alloyed with Al-Si-Ti or Si-Zr-Nb) in accordance with optimum heat treatment was found (solution: 970 °C/1h/air and ageing: 550 °C/3h/air), in order to obtain maximum service temperature of over 600 0C and ensured the good combination of strength and toughness properties. The precipitates, such as Ni3(Mo, Ti), were well controlled in lath martensite (Rm=2090N/mm2 and Rp0,2=1930N/mm2)and the presence of Si, Zr and Nb enhance structure stability at high temperature (for example the ultimate tensile strength at 5500C is about 1440N/mm2). Therefore, this new type of maraging steel was the subject of a national patent: “Maraging steel for high temperature service and heat treatment technology” – PATENT No.120356/30.08.2010.

MORPHOLOGY OF LATH MARTENSITE FORMED FROM DEFORMED AUSTENITE IN 18% Ni MARAGING STEEL

1982 ◽  
Vol 43 (C4) ◽  
pp. C4-551-C4-556 ◽  
Author(s):  
I. Tamura ◽  
K. Tsuzaki ◽  
T. Maki
Keyword(s):  
Maraging Steel ◽  
Lath Martensite

ELECTRON MICROSCOPY STUDIES OF LATH MARTENSITE

1982 ◽  
Vol 43 (C4) ◽  
pp. C4-557-C4-562
Author(s):  
B. P.J. Sandvik ◽  
C. M. Wayman
Keyword(s):  
Electron Microscopy ◽  
Lath Martensite
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