SAE/AISI 1018 carbon steel bar is one of the most widely specified low-carbon steel bar products for machined parts, shafts, pins, and studs. Its 0.18% nominal carbon content delivers an excellent balance of weldability, machinability, and case-hardening response, making it a near-universal choice for fabricators serving automotive, agricultural, hydraulics, machinery, and general engineering markets.
Huaxia-Steel supplies 1018 bar direct from Chinese mills in round, hex, square, and flat-bar profiles. Available in hot-rolled, cold-drawn, turned-and-polished, and centerless-ground conditions to meet tight tolerance requirements, with full EN 10204 3.1 mill certification and global shipping.
Product Overview
SAE/AISI 1018 is a low-carbon resulfurized steel grade standardized under SAE J403 / AISI designations. It contains nominally 0.15 – 0.20% carbon, 0.60 – 0.90% manganese, and tightly limited residual elements. The “1018” notation is widely recognized across international trade — equivalent grades include GB 15#, DIN C15 / 1.0401, JIS S15C, BS 080A15, and EN C15E.
Specifications
Standard & Grade
- Standard: SAE J403 / AISI, ASTM A29, DIN EN 10083-2 (case-hardening steels)
- Grade: SAE/AISI 1018
- Delivery condition: Hot rolled (HR), Cold Drawn (CD), Turned & Polished (T&P), Centerless Ground (CG)
- Forms: Round bar, hex bar, square bar, flat bar
- Equivalents: GB 15#, DIN C15 (1.0401), DIN C15E (1.1116), JIS S15C, EN C15E, BS 080A15, GOST Steel 15, IS 15C8
Dimensional Range
| Form | Size Range | Standard Length |
|---|---|---|
| Round bar (HR) | 5 – 250 mm (Ø) | 3 – 6 m (or cut-to-length) |
| Round bar (CD) | 5 – 100 mm (Ø) | 3 – 6 m |
| Hex bar (HR) | 8 – 75 mm (across flats) | 3 – 6 m |
| Hex bar (CD) | 8 – 70 mm | 3 – 6 m |
| Square bar (HR) | 8 – 100 mm | 3 – 6 m |
| Square bar (CD) | 8 – 80 mm | 3 – 6 m |
| Flat bar (HR) | 10 – 100 mm thick × 30 – 250 mm wide | 3 – 6 m |
| Flat bar (CD) | 5 – 50 mm × 25 – 150 mm | 3 – 6 m |
Mechanical Properties (typical by condition)
| Condition | Yield (MPa) | Tensile (MPa) | Elong (%) | Hardness (HBW) |
|---|---|---|---|---|
| Hot Rolled (HR) | ≥275 | ≥430 | ≥22 | 115 – 140 |
| Cold Drawn (CD) | ≥490 | ≥550 | ≥15 | 130 – 160 |
| Turned & Polished (T&P) | ≥490 | ≥550 | ≥15 | 130 – 160 |
| Centerless Ground (CG) | ≥490 | ≥550 | ≥12 | 130 – 160 |
| Carburized + Quenched + Tempered | ≥620 (core) | — | — | Surface 58 – 62 HRC; core 25 – 35 HRC |
Chemical Composition (Heat Analysis, %)
| C | Mn | P (max) | S (max) | Si (typical) |
|---|---|---|---|---|
| 0.15 – 0.20 | 0.60 – 0.90 | 0.040 | 0.050 | 0.10 – 0.35 |
The relatively high Mn for a low-carbon grade gives 1018 slightly better hardenability than 1020 (which has Mn 0.30 – 0.60%). This translates to finer grain and slightly more uniform case hardening. CEV is typically 0.18 – 0.22, ensuring excellent weldability without preheating for thin sections.
Subgrades and Variants
| Variant | Description | When to Specify |
|---|---|---|
| SAE 1018 (default) | Standard 0.18% carbon | Most applications |
| SAE 1018 CR | Cold rolled bar (slightly higher strength) | Cold drawing applications |
| SAE 1018 Modified | Tighter chemistry limits (P ≤0.025, S ≤0.035) | Critical case hardening |
| SAE 1018 Plus | Improved cleanliness (inclusion rating) | Fatigue-loaded parts |
| 1215 vs 1018 | 1215 is a free-machining grade with higher S; 1018 is the general-purpose baseline | Use 1215 only for high-volume automatic machining |
Heat Treatment Reference for 1018
| Process | Austenitize Temp (°C) | Quench | Tempering | Surface Hardness | Core Hardness |
|---|---|---|---|---|---|
| Carburizing (gas) | 900 – 925 | Oil or press quench | 150 – 180 | 58 – 62 HRC | 25 – 35 HRC |
| Carburizing (pack) | 880 – 920 | Oil or water | 150 – 180 | 56 – 60 HRC | 25 – 35 HRC |
| Carbonitriding | 815 – 870 | Oil | 150 – 180 | 55 – 60 HRC | — |
| Induction Hardening | Local heating to 880 – 950 | Water / polymer quench | 150 – 200 | 55 – 60 HRC | Unaffected core |
| Normalizing | 870 – 900 | Air cool | None | — | 130 – 150 HBW |
| Spheroidize Anneal | 650 – 700 (held) | Furnace cool | None | — | 110 – 130 HBW (for forming) |
Typical effective case depth (carburizing at 925 °C, 6 h): 1.0 – 1.5 mm. For thicker cases, extend time or raise temperature.
Manufacturing Standards
- SAE J403: Chemical composition of carbon and alloy steels
- SAE J412: General characteristics and heat treatments of steels
- ASTM A29 / A29M: General requirements for carbon and alloy steel bars
- ASTM A108: Standard specification for steel bar, carbon, cold-finished
- EN 10083-2: Steels for quenching and tempering / case hardening (for the equivalent EN grades)
- DIN 1651: Bright steel products (legacy German standard)
- EN 10204 3.1: Mill test certificate supplied with every heat
Typical Applications
Machined Components
- Shaft stock for pumps, gearboxes, conveyor rollers
- Pin stock for hinges, linkages, anchor points
- Spacer and bushing blanks
- Fastener blanks (bolts, studs, threaded rods)
- Hydraulic cylinder end fittings and tie rods
Fabricated & Welded Parts
- Equipment brackets and base plates
- Tractor and implement pins
- Truck and trailer suspension components
- Construction site pins and formwork hardware
Case-Hardened Parts
- Splined shafts and gear blanks
- Pinion shafts and sprockets
- Wear-resistant bushings
- Track pins and rollers
Cold Formed Parts
- Cold-headed fasteners (bolts, screws)
- Cold-drawn wire and rod
- Stampings and deep-drawn parts (sheet version)
Why Choose SAE 1018 Bar from Huaxia-Steel
- Wide size range: Round bar 5 – 250 mm in HR; hex, square, flat sections in matching sizes
- Multiple finish conditions: Hot rolled, cold drawn, turned & polished, centerless ground
- Tight tolerances: Cold-drawn bar typically h9 (or h6 / h7 by agreement)
- Surface finish: Ra 1.6 – 3.2 μm on CD; Ra 0.4 – 0.8 μm on CG
- Traceability: Every heat marked with heat number, batch number, and certified by MTC 3.1
- Custom cuts: Cut-to-length with chamfered ends available to drawing
- Global shipping: Mill-direct from China to project site or port with FOB / CIF / DDP terms
Quality Assurance
- MTC EN 10204 3.1: Independent mill certification verifying chemistry and mechanical values.
- Chemistry check: Optical emission spectroscopy on every heat.
- Mechanical test: Tensile test on every heat; hardness per batch.
- Dimensional inspection: 100% on diameter and straightness, with sample records.
- Surface inspection: Visual on 100% of pieces for cracks, seams, scabs.
- Third-party inspection: SGS / BV / TUV / Intertek on request before shipment.
Packaging & Shipping
- Hexagonal bundles: Steel-banded bundles of 500 – 2,000 kg, edge-protected
- Plastic wrap: Optional VCI paper inside the wrap for long storage
- End finish: Cut ends, chamfered, or threaded / drilled to drawing
- Container loading: 20′ GP / 40′ GP depending on bar length; typical bundle weight 1 – 2 tonnes
- Lead time: Stock sizes 2 – 4 weeks; custom specs 4 – 8 weeks
Comparing 1018 Bar with Other Machining Steels
SAE 1018 vs other commonly machined steels:
| Steel | C % (nominal) | Machinability (% of 1212) | Best Use |
|---|---|---|---|
| SAE 1212 | 0.10 | 100% | Maximum machining speed, screws; not heat-treatable |
| SAE 1215 | 0.10 | 100% (better chip control) | Automatic screw machine, parts needing no welding |
| SAE 1018 | 0.18 | 62% | General purpose, weldable, case-hardenable (baseline) |
| SAE 1020 | 0.20 | 65% | Slightly higher strength; good for induction hardening |
| SAE 1045 | 0.45 | 60% | Higher strength, through-hardenable; not as weldable |
| SAE 4140 | 0.40 + Cr-Mo | 50 – 55% | High strength alloy, oil-quenchable |
1018 sits between the high-machining but non-heat-treatable 1212/1215 family and the higher-carbon/lower-weldability 1045/4140 family. It’s the practical “default” carbon steel for machined components where weldability and case hardening may be needed.
Order Information
For an accurate quotation, please specify:
- Grade: SAE 1018 (or equivalent: GB 15#, DIN C15, JIS S15C)
- Form: Round (Ø), hex (AF), square, flat (T × W)
- Size and tolerance: Specify dimension and tolerance (h9, h11, etc.)
- Condition: Hot rolled, cold drawn, turned & polished, centerless ground
- Length: Standard or cut-to-length
- Quantity: Total weight or piece count
- Inspection: MTC only, third-party inspection, supplementary tests
- Delivery: FOB / CIF / DDP to project site or port
Get a Quote
Need SAE/AISI 1018 carbon steel bar in round, hex, square, or flat profiles? Huaxia-Steel supplies 1018 bar in hot-rolled, cold-drawn, turned-and-polished, and centerless-ground conditions from our ISO-certified Chinese mill network. EN 10204 3.1 mill certificate, third-party inspection on request, global shipping. Send your specification (grade, form, size, condition, quantity, delivery port) to [email protected] for a quotation.
