1. Why Three Grades, Not One
A stamping engineer who opens a mill catalogue for low-carbon cold rolled strip sees three names that look interchangeable: SPCC, SPCD, DC01. They are not. Each name encodes a standard, a chemistry window, and a formability tier — and specifying the wrong one is the difference between a part that draws cleanly and one that splits at the punch radius on the third stroke.
The gap between the three is not dramatic in absolute terms. All three are low-carbon (under 0.15% C), all three are cold rolled and annealed, all three are aluminium-killed for fine grain size. The difference is cumulative: tighter chemistry limits plus controlled annealing practice plus skin-pass reduction add up to a measurable spread in r-value, and r-value is the number that decides how deep you can draw before the wall thins past the safe limit.
1.1 The standards behind the names
SPCC and SPCD come from JIS G3141 (Japanese Industrial Standard, Cold-Rolled Carbon Steel Sheets and Strip). The third letter tells the quality class: C for Commercial, D for Drawing. DC01 comes from EN 10130 (European Standard, Cold rolled low carbon steel flat products for cold forming), where DC stands for Drawing Cold and the 01 denotes the commercial drawing quality class.
Because the standards are independent, the chemistry windows do not line up exactly. A certificate for SPCC will cite JIS G3141; a certificate for DC01 will cite EN 10130. Substituting one for the other without checking the actual measured values on the heat is a common source of die problems — the grade name is a promise about a range, not a guarantee of a single value.
1.2 What r-value and n-value actually measure
Two numbers dominate deep drawability: the plastic strain ratio (r-value, or Lankford value) and the strain-hardening exponent (n-value).
The r-value measures how much the material resists thinning in the thickness direction when pulled in the plane. A high r-value means the metal prefers to flow in the plane rather than thin out — exactly what a deep-drawn cup wall needs. r-value is measured in a tensile test as the ratio of width strain to thickness strain, and it is reported as an average across the rolling direction (r̄ or rm).
The n-value measures how quickly the material work-hardens as it deforms. A higher n-value means the strain distributes more evenly across the part, delaying localized necking. For drawing, both matter: r-value controls wall thinning, n-value controls how uniformly the strain spreads.
2. Chemical Composition Compared
The table below lists the maximum (or range) chemical composition limits for each grade under its governing standard. Values are typical of the latest revision; always refer to the current edition of the standard and the supplier's mill test certificate for the heat you are buying.
| Element | SPCC (JIS G3141) | SPCD (JIS G3141) | DC01 (EN 10130) |
|---|---|---|---|
| Carbon (C) | ≤ 0.15% | ≤ 0.10% | ≤ 0.12% |
| Manganese (Mn) | ≤ 0.60% | ≤ 0.45% | ≤ 0.60% |
| Phosphorus (P) | ≤ 0.10% | ≤ 0.035% | ≤ 0.045% |
| Sulfur (S) | ≤ 0.035% | ≤ 0.035% | ≤ 0.045% |
| Aluminium (Al, acid sol.) | Not specified (typ. ≥0.020%) | ≥ 0.020% | ≥ 0.020% |
Composition limits are indicative and based on standard specifications. Actual heat chemistry varies within these windows; confirm against the mill test certificate. SPCC may be supplied as rimmed or capped steel in some mills, which affects r-value consistency — ask for aluminium-killed (AK) material if formability is critical.
Three observations from the table matter for drawing:
- Carbon ceiling. SPCD has the tightest carbon limit (≤0.10%), which directly supports higher ductility. SPCC allows up to 0.15% C — a heat at the top of that range will draw noticeably worse than one at the bottom.
- Phosphorus. Phosphorus is a ferrite strengthener that raises yield strength and reduces ductility. SPCD caps P at 0.035%, DC01 at 0.045%, and SPCC at a loose 0.10%. For deep drawing, lower phosphorus is always better.
- Aluminium killing. SPCD and DC01 both specify a minimum acid-soluble aluminium of 0.020%, which ensures fine grain size and consistent r-value. SPCC does not mandate it — a non-killed SPCC heat can show scatter in r-value coil to coil, which is a problem for progressive dies.
3. Mechanical Properties by Thickness Band
Mechanical properties for cold rolled strip are not single numbers — they shift with thickness because thinner gauges require greater cold reduction, which raises strength and lowers elongation. The tables below present typical property bands by thickness range for each grade in the annealed and skin-passed ( temper-rolled ) condition. Treat these as orientation values; the supplier's certificate for your specific thickness and width is the binding reference.
3.1 Yield and tensile strength
| Grade | Thickness band | Yield strength (MPa) | Tensile strength (MPa) |
|---|---|---|---|
| SPCC | 0.30 – 0.70 mm | 200 – 280 | 300 – 380 |
| 0.70 – 1.50 mm | 180 – 260 | 280 – 360 | |
| 1.50 – 3.00 mm | 160 – 240 | 270 – 340 | |
| SPCD | 0.30 – 0.70 mm | 180 – 260 | 290 – 370 |
| 0.70 – 1.50 mm | 160 – 240 | 270 – 350 | |
| 1.50 – 3.00 mm | 150 – 220 | 260 – 330 | |
| DC01 | 0.30 – 0.70 mm | 170 – 250 | 290 – 370 |
| 0.70 – 1.50 mm | 150 – 230 | 270 – 350 | |
| 1.50 – 3.00 mm | 140 – 210 | 260 – 330 |
Typical values in the annealed + skin-passed condition. EN 10130 specifies DC01 tensile strength as 270–410 MPa (nominal thickness ≤0.7 mm) and 270–390 MPa (>0.7 mm); yield is not mandated but typically ≤280 MPa. JIS G3141 specifies SPCC/SPCD tensile strength ≥270 MPa. Actual values vary by mill and annealing practice.
3.2 Elongation
| Grade | Thickness band | Elongation A80 (%) |
|---|---|---|
| SPCC | 0.30 – 0.70 mm | 30 – 38 |
| 0.70 – 1.50 mm | 34 – 42 | |
| 1.50 – 3.00 mm | 36 – 44 | |
| SPCD | 0.30 – 0.70 mm | 34 – 42 |
| 0.70 – 1.50 mm | 38 – 46 | |
| 1.50 – 3.00 mm | 40 – 48 | |
| DC01 | 0.30 – 0.70 mm | 34 – 42 |
| 0.70 – 1.50 mm | 38 – 46 | |
| 1.50 – 3.00 mm | 40 – 48 |
A80 gauge length per JIS/EN convention. Elongation is thickness-sensitive — thinner strip shows lower elongation due to greater cold reduction. SPCD and DC01 are closely matched; SPCC typically runs 2–4 percentage points lower.
3.3 r-value and n-value
This is the table that matters most for drawing. The r-value (average, r̄) and n-value separate the three grades into distinct formability tiers.
| Grade | Average r-value (r̄) | n-value | Formability tier |
|---|---|---|---|
| SPCC | ≥ 1.2 (typ. 1.2 – 1.4) | 0.18 – 0.21 | Shallow drawing / commercial |
| SPCD | ≥ 1.4 (typ. 1.4 – 1.6) | 0.20 – 0.23 | Medium drawing |
| DC01 | ≥ 1.6 (typ. 1.6 – 1.9) | 0.21 – 0.24 | Deep drawing |
r-value and n-value are measured in the tensile test per ISO 10113 / JIS Z 2254. Values are typical for annealed + skin-passed strip at 0.7–1.5 mm. r-value can vary by direction (planar anisotropy, Δr); for asymmetric parts, ask for the 0°/45°/90° values individually. DC04 and DC06 (not compared here) reach r̄ ≥1.8 and ≥2.0 respectively for extra-deep drawing.
The spread is clear: DC01's r-value floor of 1.6 is SPCC's ceiling. For a part that needs an r̄ of 1.5 or above, SPCC is simply not a safe specification — even a good SPCC heat may fall short. SPCD covers the middle ground, and DC01 is the grade that guarantees the deep-drawing performance.
4. Drawing Depth Classification
Drawing severity is conventionally classified by the draw ratio (blank diameter / punch diameter) and the number of redraws needed. The table below maps each grade to the drawing-depth tier it can reliably handle, assuming good lubrication, proper die radii, and single-action drawing.
| Drawing tier | Typical draw ratio | SPCC | SPCD | DC01 |
|---|---|---|---|---|
| Shallow draw | ≤ 1.8 | ✓ Suitable | ✓ Suitable | ✓ Suitable (over-specified) |
| Medium draw | 1.8 – 2.1 | △ Marginal | ✓ Suitable | ✓ Suitable |
| Deep draw | 2.1 – 2.4 | ✗ Not recommended | △ Marginal | ✓ Suitable |
| Extra-deep draw | > 2.4 | ✗ Not recommended | ✗ Not recommended | △ Requires DC04/DC06 or multi-draw |
Draw ratio = blank diameter / punch diameter for a cylindrical cup. Actual limits depend on lubrication, die radius, blank holder force, and part geometry. Rectangular and irregular shapes have different limits. For production, always validate with a tryout stroke before committing to a grade.
SPCC's territory is shallow drawing and simple bending — brackets, clips, simple housings, panels with minimal depth. SPCD covers medium drawing — automotive body panels of moderate depth, appliance casings, drawn cups up to roughly 2.1 draw ratio. DC01 is the deep-drawing workhorse — fuel tanks, deep cans, motor housings, and any part where the wall must survive a draw ratio above 2.1 without splitting.
For extra-deep draws beyond 2.4, even DC01 reaches its limit. The EN 10130 ladder continues with DC04 (r̄ ≥1.8) and DC06 (r̄ ≥2.0), or the part is designed for multiple draw operations with intermediate anneals. Our SPCE deep drawing steel page covers the JIS equivalent of these higher tiers.
5. Grade Selection Decision Table
Work through the questions in order. The first column that matches your part points to the grade.
| Part characteristic | SPCC | SPCD | DC01 |
|---|---|---|---|
| Draw ratio ≤ 1.8 (shallow) | ✓ Best value | ✓ | Over-specified |
| Draw ratio 1.8 – 2.1 (medium) | Marginal | ✓ Recommended | ✓ |
| Draw ratio 2.1 – 2.4 (deep) | ✗ | Marginal | ✓ Recommended |
| Simple bending / roll forming | ✓ Best value | ✓ | Over-specified |
| Visible surface (2B/BA required) | ✓ | ✓ | ✓ |
| Tight r-value consistency (progressive die) | △ Ask for AK | ✓ | ✓ |
| Cost-sensitive, low-risk part | ✓ Best value | — | — |
| European supply chain / EN spec required | — | — | ✓ Standard |
| Japanese supply chain / JIS spec required | ✓ Standard | ✓ Standard | — |
6. Practical Notes for Buyers
Three points that come up repeatedly in RFQ conversations and are worth stating plainly.
Certificate values beat grade names. A grade name tells you the maximum allowed chemistry and the minimum guaranteed properties. It does not tell you the actual r-value of the heat sitting on your dock. For critical draws, request the measured r̄ and n-value on the mill test certificate, and set a minimum r̄ in your purchase specification rather than relying on the grade name alone.
Surface finish is a separate specification. All three grades can be supplied in 2D, 2B or BA finish. The finish does not change the drawability tier, but it does change friction at the die surface and the appearance of the finished part. Our steel surface finish guide walks through BA vs 2B vs 2D with application examples.
Edge condition matters for drawing. Slit edge burr or excessive edge wave can initiate splitting at the draw radius regardless of grade. For deep-drawn parts, specify a slit edge condition (burr height limit) and consider edge conditioning or round-edge slitting. Our edge burr guide covers the causes, prevention and acceptance limits.
HS-FINEB stocks all three grades — SPCC, SPCD and DC01 — in thicknesses from 0.30 to 3.00 mm and widths from 20 to 1250 mm, with slitting and cut-to-length processed in-house. The annealed hardness band and r-value are quoted at RFQ and reported on the inspection certificate, so your die setup stays repeatable coil to coil. For the full cold rolled product range, see the cold rolled steel strip product page.