AISI 4145 is commonly used for a variety of applications in the oil and gas sector. Used often for the manufacture of down hole drilling tools such as drill collars. Other applications include gears, shafts for hydraulic presses, rolls for paper mills, pump shafts and tool holders.

AISI 4145H is a low alloy steel suitable for downhole drilling tools such as subs, x-overs, drill collars, pup-joints and fishing tools. General engineering applications include components exposed to heavy strain, such as shafts, gear, bolts etc. AISI 4145H can also be used in hardened condition as machine parts exposed to heavy wear.