Chromium-Molybdenum high tensile steel has good ductility, shock resistance and wear resistance.AISI 4145, AISI 4145H and AISI 4145MOD are the main type of 4145 Cr-Mo steel.

AISI 4145 is a chromium molybdenum low alloy steel grade widely used in the oil and gas sectors but with a higher carbon content compared with AISI 4140. Larger diameters AISI 4145 bars are often supplied with higher Molybdenum level, 0.35% max and may be referred to as a "Drill Collar" analysis.

AISI 4145H is the upgraded type of AISI 4145. AISI 4145H has improved hardenability and is commonly used in the high strength condition with min.110 KSI yield and 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.

AISI 4145MOD is another upgraded type of AISI 4145H. Mod means the modify, that is, the tiny adjustment of chemical constituents of 4145, making steel has better hardenability. Because the inner diameter of many workpieces are less than 200 mm, which need higher performance requirements for the heat treatment, need core performance and meet the requirements, it will need to be improved in order to improve the hardenability. The typical uses of 4145H modified steel are: drilled collars, connecting rods, shafts, gears

The tiny difference in chemical composition showed below:

We can see that the difference between them are tiny and most of time they can be replaceable except the Special requirements for workpieces. AISI 4145H are the commonly used type low alloy Cr-Mo steel, more details, contact us mow!