AISI 1020 Steel:The Complete Procurement & Engineering Guide

Chemical composition, mechanical properties, heat treatment, welding guidelines, and real-world applications — everything you need to specify 1020 carbon steel with confidence.

Carbon Steel
Carburizing Grade

Low Carbon (0.18–0.23% C)
ASTM A29 / SAE J403

Excellent Weldability

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What Is AISI 1020 Steel?

AISI 1020 is a widely used low-carbon (mild) steel designated by both the AISI and SAE standards (UNS G10200). With a carbon content of 0.18–0.23%, it sits at the lower end of the plain carbon steel range, offering an optimal balance of ductility, machinability, and cost-effectiveness for general engineering applications.

Chemical Composition

Grade	C	Si	Mn	P	S
1020	0.18-0.23	0.15-0.35	0.30-0.60	≤0.04	≤0.05

International Equivalent Grades

1020 is produced under multiple standard designations worldwide:

Germany	UK	China	Japan
C22/1.0402	EN3/070M20	20#	S20C

Why Choose 1020? Six Core Advantages

Exceptional Weldability

No preheat needed for sections up to 25mm; compatible with all common welding processes

Superior Formability

Excellent cold forming, bending, stamping and drawing property; up to 50% cold reduction

Cost-Effective

One of the most economical carbon steel grades for non-critical structural components

Carburizing Capability

Ideal for case hardening when a hard wear-resistant surface with a tough ductile core is required

Good Machinability

Approximately 72% machinability rating, especially in cold-drawn condition

Wide Global Availability

Produced under multiple international standards, ensuring supply chain flexibility

1020 Steel Heat Treatment Basics

Essential processing parameters and practical guidelines for working with 1020 carbon steel in production environments.

1020 is NOT suitable for through-hardening (quench and temper) applications. Its low carbon content and lack of alloying elements result in very low hardenability. Use it in the as-supplied, normalized, or carburized condition only.

Annealing

870–925°C

Normalizing

850–900°C

Carburizing

900–950°C

Tempering

150–205°C

Stress Relieving

600–700°C

1020 Steel Mechanical Properties-Annealed Condition

Tensile Strength (UTS)	Yield Strength (0.2% offset)	Elongation (in 50 mm)	Reduction in Area	Brinell Hardness
395 MPa	295 MPa	36.5%	66%	123 BHN

Properties vary by product form (bar, plate, sheet, tube) and condition (hot-rolled, cold-drawn, normalized, carburized). Cold-drawn 1020 typically shows higher strength (440–790 MPa UTS) and hardness (125–230 BHN) but lower ductility.

1020 Steel Machining & Welding

Machining & Processing

Machinability Rating: ~72% (relative to B1112 = 100%)
Recommended Cutting Speed (HSS): 100–130 m/min (330–430 SFM) for turning
Best Condition: Cold-drawn bar machines better than annealed material
Chip Formation: Gummy chips in fully annealed condition; cold-drawn produces better chip breakage
Cold Forming: Excellent — bending, stamping, deep drawing, cold heading all perform well
Cold Reduction: Up to 50% without intermediate annealing

Welding Guidelines

Weldability Rating: Excellent
Preheat: Generally not required for sections ≤ 25mm (1 inch); preheat 100–150°C for thicker sections
Recommended Processes: SMAW, GMAW (MIG), GTAW (TIG), FCAW, SAW — all standard processes work well
Filler Metal: Use low-carbon electrodes (E6013, E7018) or matching ER70S-6 for GMAW
Post-Weld Heat Treatment: Not normally required; stress relief at 600–650°C for critical applications
Caution: Do NOT weld 1020 in the carburized or case-hardened condition — risk of cracking

1020 Steel Industry Applications & Product Forms

AISI 1020 steel is used across a wide range of industries for components where good formability, weldability, and moderate strength are required.

Automotive & Transportation

Transmission shafts and pinions (case-hardened)
Steering components and linkages
Engine mounting brackets
Fasteners, bolts, and studs (cold-headed)
Axles and spindles (light-duty)

General Machinery & Equipment

Shafts, spindles, and axles
Gears and pinions (carburized)
Pins, dowels, and ratchets
Levers, arms, and brackets
Machine tool components

Agricultural Equipment

Implement frames and structural members
PTO shafts and drive components
Fasteners and hardware
Bracket and mounting plates

Construction & Infrastructure

Structural brackets and plates
Anchor bolts and foundation hardware
Pipe and tube supports
General fabrication stock

Fastener & Hardware Industry

Cold-headed bolts, screws, and nuts
Rivets and pins
Washers and spacers
Threaded rod and bar stock

Available Product Forms For 1020 Steel

Hot Forged Round bar:Φ80-Φ1500mm

Hot Rolled Round bar:Φ14-Φ350mm

Hot Forged Square bar: Max Thickness:500mm

Flat bar/Blcoks:Thickness :120-800mm ,Width:120-1500mm

Surface Finish	Black-Forged	Black-Rolled	Rough Turned	Cold Drawn	Peeled	Polished	Grinded
Tolerance	0/+5mm	0/+1mm	0/+3mm	Best H11	Best H9	Best H9	Best h8

1020 vs 1018 vs 1045: How to Choose?

Compare 1020 against other popular carbon steel grades to find the right material for your application.

Feature	1018	1020	1045
Carbon Content	0.15–0.20%	0.18–0.23%	0.43–0.50%
Steel Type	Low Carbon	Low Carbon	Medium Carbon
Tensile Strength	390 MPa	395 MPa	565 MPa
Yield Strength	290 MPa	295 MPa	310 MPa
Weldability	Excellent	Excellent	Fair (preheat needed)
Machinability	70%	72%	60%
Through-Hardening	No	No	Yes
Carburizing	Yes	Yes	No
Relative Cost	Low	Low	Medium
Best For	General sheet metal, forming	General engineering, shafts, case hardening	Gears, axles, bolts, medium strength

Quick Selection Guide

Choose 1020 when:You need excellent weldability, good formability, and cost-effective general-purpose mechanical parts. Ideal for case-hardened components.

Upgrade to 1045 when:You need higher strength and hardness through quench-and-temper, and welding is minimal or not required.

Frequently Asked Questions

Quick answers to the most common questions about AISI 1020 carbon steel. Can’t find what you’re looking for? Contact our technical team.

Can 1020 steel be hardened and tempered?admin2026-08-08T14:38:11+08:00

Can 1020 steel be hardened and tempered?

1020 steel is NOT suitable for conventional through-hardening (quench and temper) because its low carbon content (0.18–0.23%) and lack of alloying elements result in very low hardenability. Instead, 1020 is typically used in the as-supplied, normalized, or carburized condition.

If you need a through-hardenable steel, consider medium-carbon grades like 1045 or alloy steels like 4140.

What is the difference between 1018 and 1020 steel?admin2026-08-08T14:36:35+08:00

What is the difference between 1018 and 1020 steel?

1018 and 1020 are very similar low-carbon steels with overlapping properties. The key difference is carbon content: 1018 has 0.15–0.20% C while 1020 has 0.18–0.23% C. This gives 1020 slightly higher strength and hardness, marginally better response to carburizing, and very slightly lower weldability. In practice, they are often used interchangeably for general engineering purposes.

How hard can 1020 steel get?admin2026-08-08T14:35:43+08:00

How hard can 1020 steel get?

In its standard annealed condition, 1020 steel is relatively soft at about 123 BHN (91 HRB). Through cold drawing, hardness can increase to 125–230 BHN. For maximum surface hardness, 1020 is typically carburized (case-hardened), which can produce surface hardness of 55–62 HRC while maintaining a tough, ductile core. Note: 1020 cannot be through-hardened effectively.

What is 1020 steel used for?admin2026-08-08T14:35:13+08:00

What is 1020 steel used for?

AISI 1020 is one of the most widely used general-purpose carbon steels. Common applications include: general engineering components, shafts and axles, gears and pinions (especially case-hardened via carburizing), fasteners and bolts (cold-headed), machinery parts, brackets and structural members, automotive components, and agricultural equipment parts.

Can 1020 steel be welded? Does it need preheat?admin2026-08-08T14:34:01+08:00

Can 1020 steel be welded? Does it need preheat?

Yes, 1020 steel has excellent weldability — among the best of all carbon steel grades. For sections up to 25mm (1 inch) thick, no preheating is required. For thicker sections or highly restrained joints, a preheat of 100–150°C (210–300°F) is recommended. All standard welding processes work well.

Note: do not weld 1020 in the carburized or case-hardened condition.

What is the tensile strength of 1020 steel?admin2026-08-08T14:32:35+08:00

What is the tensile strength of 1020 steel?

In the annealed condition, AISI 1020 has a typical tensile strength of approximately 395 MPa (57,300 psi) and a yield strength of 295 MPa (42,800 psi). In the cold-drawn condition, tensile strength increases significantly to 440–790 MPa depending on the amount of cold work. Brinell hardness ranges from 123 BHN (annealed) up to 230 BHN (cold-drawn).