When 42CrMo4 is normally discussed
42CrMo4 / 4140 is usually considered when the part needs higher strength, quenched-and-tempered supply, and stronger support for high-load hydraulic or rotating components.
Technical Resource
Hydraulic cylinder rod buyers often compare 42CrMo4 / 4140 and CK45 / 1045 because both can appear in rod, shaft, and machined-part discussions. The right choice depends on load, delivery condition, machining route, surface requirement, and inspection plan.

Buyer Guide
Use this guide to prepare a clearer specification and reduce back-and-forth during RFQ review.
42CrMo4 / 4140 is usually considered when the part needs higher strength, quenched-and-tempered supply, and stronger support for high-load hydraulic or rotating components.
CK45 / 1045 is commonly discussed for medium-carbon shaft and rod applications where general machining, dimensional control, and practical cost balance matter.
Confirm equivalent standard, delivery condition, diameter, length, straightness, machining allowance, surface route, MTC requirement, and whether mechanical testing or UT is needed.
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FAQ
42CrMo4 and AISI 4140 are commonly discussed as comparable Cr-Mo alloy steels, but the active order standard and property requirements should be confirmed before quotation.
CK45 can be discussed for some rod applications, but load, surface route, straightness, machining, and testing requirements must be reviewed.
Include grade or equivalent standard, diameter, length, quantity, delivery condition, application, destination, and certificate or testing requirements.
RFQ
Include delivery condition, processing requirement, destination port, testing requirements, and certificate expectations so the supply route can be reviewed clearly.