Quenching and Partitioning (Q&P) Processing of Martensitic Stainless Steels

Critical Assessment 7: Quenching and partitioning

“…Additional product types such as martensitic stainless steels have been explored more recently. [41][42][43] Thermomechanical processing of austenite and non-isothermal partitioning have been explored for steels that are not produced using continuous strip annealing facilities, [44][45][46][47][48][49][50][51][52] including some facility related considerations. The process related developments have also evaluated Q&P thermal signatures within other manufacturing environments, such as hot stamping/press quenching and various tubemaking scenarios.…”

“…Residual ductility of press hardened parts (in service) is limited, and Q&P processing has been investigated in a hot stamping context to enhance tensile ductility of formed parts with encouraging results. 56,91 Application of Q&P to other sheet steel product areas such as hot rolled carbon 92 and stainless steel [41][42][43]93 also remain fruitful focus areas. Coil cooling may be employed in the hot strip mill to obtain carbon partitioning, 92 following controlled run-out table cooling and coiling.…”

Microstructural Evolution and Carbides in Quenched Ultra-low Carbon (Fe–C) Alloys

“…[1][2][3][4][5][6][7][8][9][10][11] Upon quenching, both M s (martensite start temperature) and M f (martensite finish temperature) decrease with the increasing of carbon content, and also the M f decreasing rate is faster than that of M s . 7,12,13) The interstices in iron are of two types, surrounded respectively by a tetrahedron of 4 atoms and by an octahedron of 6 atoms.…”

Thermal and deformation-induced phase transformation behavior of Fe–15Cr–3Mn–3Ni–0.1N–(0.05–0.25)C austenitic and austenitic–martensitic cast stainless steels

“…The premature fracture of RT tensile specimens is attributed to the presence of as-quenched αʼ-martensite and/or the early deformation-induced transformation of the austenitic constituent with a low mechanical stability at RT. The presence of untempered αʼ-martensite with high interstitial contents can facilitate the crack formation and lead to brittle fracture without post-uniform elongation [42]. Although fracture in alloys with higher interstitial contents was postponed to higher strains, they exhibited a higher sensitivity to the embrittlement caused by αʼ-martensite formation.…”

“…11c, the fraction of deformation-induced αʼ-martensite remains negligible for almost all alloys. The small fractions of deformation-induced αʼ-martensite in NC15, NC20, and NC25 alloys are expected to have formed near the surface due the reduced stability of austenite as a result of the local loss of C and N. The absence of deformation-induced αʼ-martensite in NC05 and NC10 alloys with an already high fraction of as-quenched martensite might then have been caused by a process similar to that occurring during the quenching and partitioning (Q&P) processing [42,49,50]. Nevertheless, due to the short diffusion distance of interstitial atoms within the timeframe of tensile tests at 200°C (approximately 20 min), a uniform interstitial concentration profile in the austenite may not be achieved.…”