4118 Round Bar: Material Profile
4118 is intended for machining or forming before case hardening, with chromium and molybdenum improving hardenability over plain-carbon alternatives.
Specify case depth, hardness, core-property targets, heat-treatment responsibility, and any grain-size or cleanliness requirements.
Purchase to the controlling ASTM, SAE, AMS, or customer specification. Section size, supply condition, mechanical properties, surface limits, testing, and heat/lot traceability can change the acceptable material and processing route.
Key Characteristics
- Good carburizing response
- Improved hardenability
- Tough low-carbon core
- Machinable before heat treatment
Common Applications
- Gears and pinions
- Shafts and arbors
- Bushings and sleeves
- Case-hardened machine parts
Specification Requirements
Identify the governing specification and revision, product form, section size, condition, mechanical properties, testing, and certification requirements. The purchase specification and material certification govern the order.
