41L40 / 41L42 Oil-Hardening Chromium-Molybdenum Leaded Alloy Steel
41L40 is the free machining version of Chromium-Molybdenum. The addition of a small amount of lead to the chemistry plus cold drawing increases the average machinability rating to 86%. This leaded grade can be heat treated the same as a standard 4140 to achieve similar hardness and strength. Impact toughness is somewhat lower for the leaded grade for hardnesses exceeding 35 HRC. 41L40 works well in screw machines. It is sometimes used in the as received condition but is normally heat treated prior to use.
These grades are capable of good strength and wear resistance, have excellent toughness and good ductility, and have the ability to resist stress and creep at prolonged high temperatures (up to 1000deg F). Leaded grades have greatly improved machinability, but should not be used in applications over 400deg F. Elevated temperatures cause lower ductility in leaded grades.
Common applications include Drill collars, kelly bars, bolts, subs, couplings, reamer bodies, rotary table shafting, oil well tool joints, axle shafts, valves, high-temperature bolts, sprockets, trailer axles, winch shafts, piston rods, rams, hydraulic machinery shafts, precision lead screws, chain links, spindles, stay bolts, tractor axles, tractor arms, zinc die casting dies.
41L40 HT (Heat Treated)
41L40 Mod (Modified)
41L40 QT (Quenched & Tempered)
41L42 ANN (Annealed)
41L42 HT (Heat Treated)
41L42 QT (Quenched & Tempered)
41L42H HT (Heat Treated)
ASTM A-29 GENERAL REQUIREMENTS FOR CARBON & ALLOY BARS, WROUGHT & COLD-FINISHED
ASTM A-108 , STEEL BARS, CARBON AND ALLOYS, COLD-FINISHED
ASTM A-304 STEEL BARS, ALLOY, SUBJECT TO END-QUENCH HARDENABILITY REQUIREMENTS
ASTM A-331 STEEL BARS, ALLOY, COLD-FINISHED
ASTM A-434 SPECIFICATION FOR STEEL BARS, ALLOY, HOT-WROUGHT OR COLD-FINISHED, QUENCHED AND TEMPERED
- Hex Bar