Release time：2020-01-16 18:44 Browse：
When producing Grade 10.9 extra-long screws, two commonly used materials are SCM435 and 40Cr. Both meet the required mechanical strength, but differ in performance characteristics:
SCM435 is a chromium-molybdenum alloy steel with excellent hardenability, high fatigue resistance, and superior tempering stability. It’s ideal for screws that require both strength and toughness, especially under high stress or vibration.
40Cr is a medium carbon alloy steel known for its good machinability and cost-effectiveness. While it provides sufficient tensile strength and hardness after heat treatment, it has slightly lower toughness and fatigue resistance compared to SCM435.
Heat treatment response: SCM435 responds better to quenching and tempering, achieving more uniform core and surface hardness, which is important for very long screws.
Applications: Choose SCM435 when the screw is used in critical structural or load-bearing applications. Opt for 40Cr in general-purpose industrial use where cost is a concern and mechanical loads are moderate.
Summary:
Use SCM435 for applications demanding higher toughness and fatigue life. Choose 40Cr for projects with lower budgets but still requiring strong, reliable fasteners.
