high tensile 4140 induction hardened chrome bar made from chrome plated steel are typically used in applications where there are heavy duty conditions – often corrosive. The steel contains increased levels of alloying elements which delivers a high grade steel with superior tensile strength exhibiting good machining.
42CrMo4 chrome plated bar is manufactured from low-alloy chromium-molybdenum steel and supported by an induction hardened case offering greater strength and resistance to mechanical damage from external impact. It is used in applications requiring greater yield strength in combination with greater surface impact resistance.
WE ALSO PRODUCE:
Large size honed bore tube;
|Australia||AS 1444 – 1996 4140|
|Germany||W.Nr 1.7223 41CrMo4
W.Nr 1.7225 42CrMo4
|Great Britain||BS970 – Part 3 – 1991 709M40
BS970 – 1955 EN19A
|Japan||JIS G 4105 SCM 440|
|USA||ASTM A29/A29M – 91 4140
|Chemical Composition (Base Material)|
|Min. %||Max %|
4140 hard chrome plated bar has very good machinability, similar to 4140 uncoated bar. Machining however should commence beneath the chrome plating, or at the unchromed surface at the end of the bar. To protect the polished chrome surface, soft materials such as copper, aluminium or mild steel should be used as clamping materials and any particles of hard chrome should be removed immediately to avoid scratching. Otherwise all machining operations may be carried out satisfactorily.
4140 has limited weldability. Welding the hard chrome bar in the hardened and tempered‘as supplied’ condition is not recommended and should be avoided if at all possible as the mechanical properties will be altered in the area of the weld heat affected zone. If welding is necessary, first remove the cardboard tube protection form the area that will be affected by heat (otherwise corrosion of the plating can be caused by fumes emitted from the cardboard). Preheating to 200 to 300°C is strongly recommended. The upper limit should not be exceeded as there is a risk of deterioration in the chrome layer. 4140 can be friction welded, however, precautions are necessary in order to limit the formation of undesirable micro structures in the welded zone. Consult your welding consumables supplier before commencing.