Commercial Production · Alloy Steel · Chromium-Molybdenum Alloy Steel Bar

4120 Round Steel Bar

A low-carbon chromium-molybdenum alloy used for carburized parts requiring a hard case and tough core.

Purchase to your specification

4120 for production and repeat supply.

Buying 4120 for machining, forging, or component production? Send your dimensions, condition, and quantity per order. For repeat supply, include annual usage and release timing, or attach your existing RFQ.

Size & supply condition: State the diameter, length, and required condition. We confirm the available supply route against your order.
Finished to your requirement: Include production cutting, surface finish, tolerances, and any required heat treatment. Processing is reviewed with the material requirement.
Documentation & delivery: Specify mill certifications, testing, traceability, delivery date, and ship-to location so they can be included in the quote.

A grade name is the starting point. The governing specification, condition, dimensions, and testing define the material to be quoted.

Read the 4120 material profile ↓

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Your 4120 requirement

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Quantity / WeightCommercial requirements from 3,000 lb through truckload quantities.

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4120 Round Bar: Material Profile

4120 offers alloy hardenability with low core carbon, supporting machining and forming before case hardening.

The carburizing cycle, case depth, hardness, and core-property requirements should be defined for the finished component.

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 case-hardening response
Tough low-carbon core
Alloy hardenability
Machinable before heat treatment

Common Applications

Gears and pinions
Bushings and sleeves
Shafts and arbors
Wear-resistant machine components

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.