Meta Description: Compare AISI 1018 vs 1020 carbon steel: chemical composition, mechanical properties, machinability, weldability, price per ton, and supplier selection guide for procurement managers.
When sourcing carbon steel from China, two of the most commonly ordered low-carbon grades are AISI 1018 and AISI 1020. At first glance, these two grades look nearly identical — both contain approximately 0.18–0.23% carbon and share similar mechanical properties. But for procurement managers, engineers, and quality inspectors, the subtle differences between 1018 and 1020 can significantly impact machining performance, welding quality, and total project cost.
This guide breaks down the 7 critical differences between AISI 1018 and 1020 carbon steel, including chemical composition, mechanical properties, machinability ratings, weldability, formability, and typical FOB China pricing. We also cover equivalent grades across JIS, DIN, and GB standards so you can cross-reference when sourcing from multiple markets.
1. Chemical Composition: What Separates 1018 from 1020
While both grades fall under the low-carbon steel category, the difference in carbon and manganese content creates measurable performance gaps.
| Element | AISI 1018 | AISI 1020 | Impact |
|---|---|---|---|
| Carbon (C) | 0.15–0.20% | 0.18–0.23% | Higher C in 1020 → slightly harder, stronger |
| Manganese (Mn) | 0.60–0.90% | 0.30–0.60% | Higher Mn in 1018 → better hardenability, wear resistance |
| Phosphorus (P) | ≤ 0.040% | ≤ 0.040% | Same — impurity control |
| Sulfur (S) | ≤ 0.050% | ≤ 0.050% | Same — machinability factor |
| Iron (Fe) | Balance | Balance | — |
Key insight for buyers: AISI 1018 has nearly double the manganese of 1020. Manganese improves hardenability and tensile strength without significantly reducing ductility. This makes 1018 marginally stronger and more wear-resistant than 1020, despite having a slightly lower maximum carbon content.
2. Mechanical Properties: Tensile, Yield, and Hardness
The mechanical property differences between 1018 and 1020 are most visible in cold-drawn condition, which is the typical delivery state for both grades.
| Property | AISI 1018 (Cold Drawn) | AISI 1020 (Cold Drawn) | AISI 1020 (Hot Rolled) |
|---|---|---|---|
| Tensile Strength (MPa) | 440–490 | 420–470 | 380–440 |
| Yield Strength (MPa) | 370–420 | 350–390 | 210–250 |
| Elongation (%) | 15–20 | 15–22 | 25–36 |
| Hardness (HB) | 126–163 | 121–149 | 111–137 |
| Reduction of Area (%) | 40–50 | 45–55 | 50–60 |
What this means for your order:
- 1018 is stronger — approximately 5–8% higher tensile and yield strength. Choose 1018 when your component needs better load-bearing capacity.
- 1020 is more ductile — higher elongation and reduction of area. Choose 1020 when deep drawing, bending, or cold forming is required.
- Hot-rolled 1020 is the most formable option but the softest — ideal for structural applications where strength is secondary to shape complexity.
3. Machinability: Which Grade Cuts Better
Machinability is a top concern for CNC shops and component manufacturers. Here’s the practical comparison:
| Machining Factor | AISI 1018 | AISI 1020 |
|---|---|---|
| Machinability Rating (AISI 1212 = 100%) | ~70% | ~65–68% |
| Surface Finish Quality | Excellent | Very Good |
| Chip Formation | Short, consistent | Slightly gummy |
| Tool Wear Rate | Moderate | Moderate-Low |
| Recommended Cutting Speed (m/min) | 80–110 | 75–100 |
Buyer’s takeaway: AISI 1018 machines slightly better than 1020 due to its higher manganese content and more favorable chip-breaking characteristics. For high-volume CNC production, 1018 often delivers 5–10% better throughput. However, the difference is small enough that either grade works well for most machining applications — the choice should be driven by final mechanical requirements, not machinability alone.
4. Weldability and Formability Comparison
Both grades belong to the low-carbon category and exhibit excellent weldability. Carbon equivalent (CE) values for both are well below the 0.40 threshold where preheating becomes necessary.
| Factor | AISI 1018 | AISI 1020 |
|---|---|---|
| Weldability Rating | Excellent | Excellent |
| Preheating Required | No (sections < 25mm) | No (sections < 25mm) |
| Post-Weld Heat Treatment | Optional | Optional |
| Cold Forming / Bending | Very Good | Excellent |
| Deep Drawing Suitability | Good | Excellent |
| Forging Temperature Range | 900–1250°C | 870–1250°C |
Critical note for buyers: When your final product requires extensive forming or deep drawing, specify AISI 1020. Its lower manganese content and slightly lower strength make it more forgiving during cold forming operations. For welded assemblies where post-weld machining is planned, 1018’s higher strength can be an advantage.
5. Surface Condition and Dimensional Tolerance
How you specify surface finish and tolerance directly affects delivered price. Here’s what Chinese mills and processors typically offer:
| Specification | AISI 1018 Cold Drawn | AISI 1020 Cold Drawn | AISI 1020 Hot Rolled |
|---|---|---|---|
| Surface Roughness (Ra) | 0.8–1.6 µm | 0.8–1.6 µm | 3.2–6.3 µm |
| Diameter Tolerance (round bar) | h9–h11 | h9–h11 | ±0.4–0.8 mm |
| Straightness | 0.5–1.0 mm/m | 0.5–1.0 mm/m | 2–4 mm/m |
| Scale / Oxide Layer | None | None | Present (removable) |
Procurement tip: If your component requires a bright, scale-free surface without additional processing, always specify cold-drawn (CD) condition for either grade. Hot-rolled 1020 will require pickling, shot blasting, or machining to remove the mill scale — adding $15–30/ton to your total processing cost.
6. Price Comparison: FOB China (2025–2026)
Pricing varies by mill, order volume, and processing state. Below are approximate FOB China price ranges for reference:
| Product Form | AISI 1018 (USD/ton FOB) | AISI 1020 (USD/ton FOB) |
|---|---|---|
| Hot Rolled Round Bar (20–100mm) | 520–580 | 500–550 |
| Cold Drawn Round Bar (10–80mm) | 620–680 | 590–650 |
| Cold Rolled Steel Plate (1.5–6mm) | 640–700 | 610–670 |
| Hot Rolled Steel Plate (6–50mm) | 530–590 | 510–560 |
Why 1018 costs more: The higher manganese content in 1018 requires more precise furnace chemistry control and slightly more expensive alloying additions. The price premium is typically $20–50/ton — modest but worth factoring into large-volume orders.
Order volume tipping point: For orders above 100 metric tons, many Chinese mills will produce either grade at nearly the same price. The cost difference becomes negligible compared to logistics and processing costs.
7. Equivalent Grades: Cross-Referencing Across Standards
When sourcing from multiple countries or specifying to different standards, equivalency tables are essential:
| Standard | 1018 Equivalent | 1020 Equivalent |
|---|---|---|
| JIS (Japan) | S15CK / S17C | S20C / S22C |
| DIN (Germany) | C15 / 1.0401 | C22 / 1.0402 |
| GB (China) | 15# / 15Mn | 20# / 20Mn |
| EN (Europe) | C15E / C16E | C22E |
| BS (UK) | 080A15 | 070M20 |
Important for China sourcing: When ordering from Chinese mills, specify the GB grade (15# for 1018 equivalent, 20# for 1020 equivalent) alongside the AISI designation. This ensures the mill’s quality control team uses the correct internal specification and avoids confusion during production.
Which Grade Should You Choose? Decision Checklist
Use this quick checklist to determine whether 1018 or 1020 is right for your application:
Choose AISI 1018 When:
- [ ] Final component requires higher tensile/yield strength
- [ ] Product will be CNC machined in high volumes
- [ ] Better surface finish (cold-drawn) is required
- [ ] Wear resistance is a consideration
- [ ] Carburizing or case hardening is planned
Choose AISI 1020 When:
- [ ] Deep drawing or complex cold forming is required
- [ ] Maximum ductility is the priority
- [ ] Hot-rolled stock is acceptable (lower cost)
- [ ] Welded assemblies with minimal post-processing
- [ ] Forging is the primary manufacturing process
FAQ: 1018 vs 1020 Carbon Steel
Q1: Can AISI 1018 and 1020 be used interchangeably?
In many applications, yes — but not always. For simple structural components, brackets, and non-critical parts, the two grades are functionally interchangeable. For precision-machined components, heat-treated parts, or deep-drawn products, the differences in strength, machinability, and formability become significant. Always consult your engineering specification before substituting.
Q2: Which grade is better for carburizing?
Both can be carburized, but 1018 generally produces better case depth uniformity because of its higher manganese content, which promotes carbon diffusion. The resulting case hardness is similar (HRC 58–62 after quenching), but 1018 tends to achieve target case depth slightly faster.
Q3: What’s the typical lead time for 1018 vs 1020 from Chinese mills?
Both grades are mass-produced commodity products. Standard lead times are 15–30 days for stock sizes (10–80mm round bar, 1.5–12mm plate). Non-standard sizes may require 30–45 days. 1020 has slightly wider stock availability due to higher production volumes globally.
Q4: Do I need to specify grain size or inclusion content?
For standard applications, no. For critical components (automotive, pressure vessels), specify fine grain practice (ASTM grain size 5 or finer) and inclusion ratings per ASTM E45. This typically adds $10–20/ton to the base price but significantly improves fatigue life.
Q5: How do I verify that delivered material is actually 1018 and not 1020?
Request a Mill Test Certificate (MTC) per EN 10204 3.1 with every shipment. The MTC must show actual chemical composition (not just nominal) from the cast analysis. For critical orders, arrange third-party PMI (Positive Material Identification) inspection using handheld XRF or OES spectrometers before shipment.
Source Your 1018 & 1020 Carbon Steel from a Trusted China Supplier
At Huaxia Steel, we supply both AISI 1018 and 1020 carbon steel in round bar, flat bar, plate, and custom-cut dimensions. Every shipment includes a full EN 10204 3.1 Mill Test Certificate, and we offer third-party inspection (SGS, Bureau Veritas, TÜV) upon request.
Our technical team can help you select the right grade, specify the correct delivery condition (hot-rolled, cold-drawn, or annealed), and arrange ocean freight to your destination port.
→ Request a Quote for AISI 1018 & 1020 Carbon Steel
*Free technical consultation · EN 10204 3.1 MTC included · FOB/CIF/CFR worldwide shipping*
