AISI 4145H 4145 G41450 SCM445 Alloy Steel Seamless Round Tube

This alloy is used in the oil and gas industry as forged down-hole drilling tools such as drill collars. Other applications are forged gears, shafts for hydraulic presses, rolls for paper mills, pump shafts and tool holders

Standard：ASTM A519

Dimensions：Outer diameter: 83-254 mm, Wall thickness: 7 to 60 mm, length: not more than 12 meters.

Tolerance for OD and ID：

Cold drawn: within ±0.2mm

Cold rolled: within ±0.1mm

Tolerance for Wall Thickness：

Hot rolled: within +/-5%,

Cold drawn: within 0.6mm

Process：Hot Rolled, Cold Drawn, Precision Rolled

 

Delivery Condition：Hot rolled, Cold drawn, Annealed, Normalized, Quenched and tempered.

Surface Condition：Black surface, Rough turned, Peeled.

Annealing

Parts should be heated slowly to 1470-1560ºF ( 800 – 850ºC), soaked and furnace cooled to 900ºF (480ºC) then air cooled.

Normalizing

A typical normalizing temperature for 4145 forgings is 1600ºF (870ºC), but based on production experience this temperature may vary from 100ºF (38ºC) above to 50ºF (10ºC) below this figure. If normalizing is carried out before a hardening and tempering treatment, then the upper temperature range is used; if normalizing is the final treatment then the lower range is used.

Hardening

The austenitizing temperature for this grade is in the range 1500-1550ºF (815-845ºC). Parts should be slowly heated to this temperature, soaked and oil quenched. Parts should be tempered as soon as they reach room temperature.

Tempering

Parts will be tempered between 1020-1300ºF (550-700ºC) for 2 hours per inch (25 mm), then air cooled. Reduced impact values will be obtained on tempering at 500ºF (260ºC) or at 750 to 1025ºF (340 to 550ºC).

The optimum combination of strength and toughness is obtained from a microstructure that is tempered martensite. If very high strength is required then tempering is carried out at a low temperature – in fact this is a stress relief – when lightly-tempered martensite will result.