This article draws upon the Metal Materials Encyclopedia and the Chinese national standard GB/T 699-2015 to provide a detailed analysis of the performance characteristics and processing essentials of 08F deep drawing steel. 08F is one of the lowest carbon content rimmed steels among high-quality carbon structural steels, offering exceptional cold stamping formability and deep drawing capability. Its unique combination of low carbon and minimal silicon content makes it a preferred material for intricate and high-precision forming operations in various manufacturing sectors.
1. Basic Information of 08F
08F is a high-quality carbon structural steel conforming to the GB/T 699-2015 standard. The designation “08” indicates an average carbon content of approximately 0.08%, while “F” denotes rimmed steel (Rimmed Steel). This steel grade features an extremely low carbon content and a very low silicon content (≤0.03%), making it a typical deep drawing steel suitable for cold stamping, deep drawing, cold bending, and other forming processes. Due to its extremely low silicon content, it exhibits excellent surface quality, making it ideal for manufacturing automotive body panels, fuel tanks, enameled products, and various stamped structural components. In practice, the low inclusion density and fine grain structure of 08F further enhance its ability to withstand severe deformation without surface defects, a critical factor in automotive and appliance industries.
2. Chemical Composition
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.05-0.11 |
| Silicon (Si) | ≤0.03 |
| Manganese (Mn) | 0.25-0.50 |
| Phosphorus (P) | ≤0.035 |
| Sulfur (S) | ≤0.035 |
| Chromium (Cr) | ≤0.10 |
| Nickel (Ni) | ≤0.30 |
| Copper (Cu) | ≤0.25 |
The chemical composition is tightly controlled to balance formability and strength. The low silicon and manganese levels minimize solid solution strengthening, while the tight limits on phosphorus and sulfur help maintain ductility and reduce the risk of hot shortness during processing. This composition is deliberately designed to achieve a fine-grained ferritic microstructure that can accommodate large plastic strains without cracking.
3. Mechanical Properties
| Property | Value | Condition |
|---|---|---|
| Tensile Strength | ≥295 MPa | Normalized |
| Yield Strength | ≥175 MPa | Normalized |
| Elongation | ≥35% | Normalized |
| Reduction of Area | ≥60% | Normalized |
| Hardness | ≤131 HB | Hot-rolled or Annealed |
Typical Properties of Cold-Rolled Sheet (Annealed):
| Property | Value |
|---|---|
| Tensile Strength | 275-390 MPa |
| Yield Strength | 140-230 MPa |
| Elongation | ≥38% |
| Erichsen Cupping Value (IE) | ≥10.5 mm |
These mechanical properties underline the excellent ductility and low strength of 08F, which are essential for deep drawing operations. The high elongation and reduction of area values ensure that the material can undergo severe plastic deformation without failure, while the low hardness facilitates ease of cutting and forming in subsequent CNC operations. In practice, the annealed cold-rolled sheet exhibits a yield ratio (YS/TS) typically below 0.6, further enhancing its stretch formability.
4. Heat Treatment Performance
As a low-carbon rimmed steel, the heat treatment characteristics of 08F are distinct:
- Normalizing: 910-940°C, air cooling, to homogenize the microstructure and eliminate banding segregation.
- Annealing: 680-720°C, slow cooling, to relieve cold working stresses and restore plasticity.
- Carburizing: Surface carburizing (920-940°C) can be performed to increase surface wear resistance without reducing core toughness.
- Not applicable: Quenching + tempering (quenching and tempering) because the carbon content is too low to provide a significant increase in hardness after quenching.
These heat treatments are tailored to either enhance uniformity (normalizing) or recover ductility after cold work (annealing). Carburizing is occasionally used when a combination of a wear-resistant surface and a tough core is required, although the low carbon core remains soft. It is important to note that due to the rimmed nature, internal segregation may occur, and normalizing at the upper end of the temperature range is recommended for thicker sections to reduce banding.
5. Typical Applications
- Automotive manufacturing (body panels, fuel tanks, exhaust mufflers)
- Enameled products (bathtubs, water heater liners)
- Appliance housings (refrigerator and washing machine panels)
- Cold stamping parts (connecting plates, brackets, heads)
- Daily hardware (barrels, cans, box-type containers)
- CNC machined parts (precision trimming, drilling, and tapping after stamping)
The versatility of 08F extends across industries requiring deep drawing and complex shapes. Its ability to form large, seamless parts with excellent surface finish makes it indispensable for visible and functional components. In automotive body applications, the consistent formability of 08F helps reduce scrap rates and ensures tight dimensional tolerances.
6. CNC Machining Performance
CNC machining characteristics of 08F:
- Cutting performance: The very low carbon steel tends to be soft and sticky, prone to built-up edge formation; sharp tools with large rake angles must be used.
- Cutting speed: 180-280 m/min (coated carbide tools).
- Tool selection: Ultra-fine grain carbide, TiN or TiAlN coated, rake angle 15-20°.
- Cooling: Adequate cutting fluid is essential; emulsion concentrate at 5-8% is recommended.
- Precision control: Due to the softness and susceptibility to deformation, clamping forces must be uniform to avoid surface damage.
When machining 08F, the primary challenges are chip control and surface finish. Using sharp, coated inserts with positive geometries helps reduce cutting forces and minimize built-up edge. The recommended cutting parameters are suitable for turning, milling, and drilling operations, but careful attention to feed rates is needed to prevent tearing or burr formation. For tapping, spiral-flute taps with proper lubrication are advisable to reduce torque and thread distortion.
7. Purchasing Guide
Market Price Reference (2025 Market Conditions):
- Cold-rolled sheet (0.5-3mm): 5-8 RMB/kg
- Hot-rolled plate (3-10mm): 4-6 RMB/kg
- Cold-rolled strip: 5.5-8.5 RMB/kg
- Round bar/wire: 4.5-6.5 RMB/kg
Pricing of 08F is influenced by sheet thickness, surface finish requirements, and order volume. For deep drawing applications, it is critical to specify the appropriate temper (e.g., annealed or skin-passed) and to verify that the material meets the required Erichsen cupping values. Buyers should also consider sourcing from reputable mills that provide full mill test certificates to ensure compliance with GB/T 699-2015. The relatively low cost of 08F, combined with its excellent formability, makes it a cost-effective choice for high-volume stamping operations.
8. Data Sources
- GB/T 699-2015 High-quality carbon structural steels
- Metal Materials Encyclopedia – 08F specific entry
- Baosteel Product Handbook
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