Alloy Steel: Choosing Case or Through Hardening

Alloy steel is a family, not a machinable stock specification. The first useful split is between a component needing a hard case and one needing strength through its section. Material reference.

Choosing Case or Through Hardening

Compare 8620 for a case-focused enquiry, 4130 for a tube or weldment review, and 4340 for a highly loaded shaft review. These are routes to investigate, not interchangeable substitutes. Define the failure mode before narrowing the grade list.

Manufacturing and acceptance checks

Send a drawing showing the controlling section, load, environment and critical surfaces. Request alternative quotations in explicit delivery and final conditions. Compare treatment, finishing and inspection costs with the stock cost; require approval before the selected grade or process changes.

Compare related options

• 8620 Steel
• 4130 Steel
• 4340 Steel

Reference and scope

Baosteel: structural and spring steel grade families provides material or specification background. The checks above are purchasing guidance; final acceptance values must come from the agreed grade, product specification and condition.

Send a drawing and material requirements for review. Include quantity, critical dimensions and the inspection evidence required with delivery.