摘要:

AbstractThe tensile properties of a metastable chromium–manganese steel are influenced by the deformation inducedγ→ε→α′martensitic transformation. While beneficial in increasing the strain hardening rate and ultimate tensile strength, the presence of substantial amounts ofε-martensite can lead to a brittle, transgranular fracture mode. An investigation has been made of the effect of prior thermomechanical processing on transformation and plastic deformation in a 10Cr–18Mn steel. Two different approaches were used: low temperature deformation and subsequent heat treatment, and high temperature deformation alone. The influence of these treatments on stress–strain behaviour and fracture is discussed. Transformation kinetics were studied by means of X-ray diffraction and magnetic measurements. Microstructural observations have shown that dislocation substructures introduced by prior deformation inhibit transformation by acting as barriers to the growth ofε-platelets. The resultant decrease in the volume fraction of martensite leads to an increase in ductility and the appearance of a region of non-uniform elongation before failure.MST/1280

ISSN:0267-0836    

DOI:10.1179/mst.1991.7.1.71

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractThe conditions for dynamic recrystallisation and dynamic recovery in AISI 321 type steel were investigated and the value of activation energy of the hot deformation process was determined. The conditions of static annealing after hot forming must be chosen to ensure full recrystallisation. The annealing treatment and the composition of the steel necessary to achieve a fully recrystallised structure in large diameter tubes obtained by pilger milling were determined.MST/1330

ISSN:0267-0836    

DOI:10.1179/mst.1991.7.1.78

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractA process for producing a low pearlite steel containing small amounts of niobium and vanadium is described. Controlling rolling followed by a short annealing treatment results in grain refinement, precipitation strengthening, and matrix recovery, and produces plate with improved strength at increased toughness levels. The process, which has been successfully applied in practice, obviates the need for crystallisation control by continuous casting.MST/1329

ISSN:0267-0836    

DOI:10.1179/mst.1991.7.1.83

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractProcess modelling methods have been applied to the thermal treatment of aluminium alloys. A model describing the development of microstructure and yield strength during isothermal aging of heat treatable alloys has been developed. This model is illustrated by means of novel‘iso-yield diagrams’. For non-heat-treatable alloys, a similar diagram for recrystallisation of cold rolled material is derived empirically. The isothermal models and diagrams are then applied to processes in which the temperature varies with time, using the concept of the‘kinetic strength’of a thermal cycle. The duration of an isothermal treatment at the peak temperature of the cycle is found; this has the same driving force for kinetic change. Of particular interest is the loss in strength in the heat affected zone of welded joints.MST/1272

ISSN:0267-0836    

DOI:10.1179/mst.1991.7.1.85

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

ISSN:0267-0836    

DOI:10.1179/mst.1991.7.1.89

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor