AISI 1040 Hollow bar Seamless Pipe

AISI 1040 Hollow bar


Hollow Section: Round
Thickness: 0.6-100 mm
Diameter: 5-200 mm
length: not more than 12 meters.


AISI 1040 Chemistry :

Carbon: 0.37 - 0.44
Manganese: 0.6 - 0.9
Phosphorus: 0.04 max
Sulphur: 0.05 max



C1040 is a medium carbon, medium tensile steel supplied as forged or normalized.


This grade of steel is used for forged parts where the strength and toughness of the material are appropriate. C1040 may be used for the manufacture of forged crankshafts and couplings, along with a range of parts where the properties of heat-treated C1040 are suited to the application.


C1040 is forged from 2200ºF (1205ºC) down to a temperature in the region of 1650ºF (900ºC) The actual forging and finishing temperatures will depend on a number of factors, including overall reduction during forging and complexity of part being forged.
Experience alone will determine near exact values for these two parameters.
Parts are air cooled after forging.



Full annealing of small C1040 forgings is carried out from 1450-1600ºF (840-890ºC)

followed by furnace cooling at 50ºF (28ºC) per hour, to 1200ºF (650ºC) soaking and air cooling.


The normalizing temperature range for this grade is typically 1600-1650ºF (870-900ºC)
Normalizing is followed by cooling in still air. When forgings are normalized before hardening and tempering or other heat treatment, the upper range of the normalizing temperature is used. When normalizing is the final treatment, the lower temperature range is used.


Hardening of this grade is carried out from an austenitizing temperature of 1525-1575ºF (830-860ºC) followed by oil or water quenching.

Flame and induction hardening may be carried out by heating quickly to the desired case depth and quenching in water or oil. This should be followed by a tempering treatment at 300-400ºF (150-200ºC) to reduce stresses in the case without affecting its hardness. A hardness of Rc 50-55 may be obtained by surface hardening.


Tempering after normal hardening and oil or water quenching is carried out at 750-1260 ºF (400-680ºC) to give the required mechanical properties as determined by practical experience.


Machinability of C1040 is good providing the full annealing cycle described above is used, ensuring a coarse lamellar pearlite to coarse spheroidite microstructure.


This grade is readily welded with the correct procedure. Welding in the through-hardened or flame or induction-hardened conditions is not recommended.

Low-hydrogen electrodes are recommended together with preheat at 300-500ºF (150-260 ºC.) to be maintained during welding, Cool slowly and stress relieve where possible.


UNS G10400, ASTM A29, ASTM A108, ASTM A510, ASTM A519, ASTM A546, ASTM A576, ASTM A682, MIL SPEC MIL-S-11310 (CS1040), SAE J403, SAE J412, SAE J414, DIN 1.1186, JIS S 40 C, BS 970 060A40, BS 970 080A40, BS 970 080M40 (EN8), BS 2 S 93