Product Introduction：
Standard: GB/T3639,DIN2391/C,EN10305-1,EN10305-4
Heating treatment: NBK, GBK, BKS, BK
Surface treatment: Bright, galvanized, phosphated
Material: ST37.4,ST35,ST45,ST52,E235,E355
Size: OD 4*WT 0.5mm -OD60*WT8mm
Length: Fixed Length 6 meters or 5.8 meters, Random Length 2-12 meters or as requests of customers
Feature:
Black phosphated on both sides of pipe
The phosphated coating in delicate, high lubricity, uniform color
Good looking in appearance
High anti corrosion & anti rust
Suitable for painting, have strong adhesion
Chemical Composition:
| Steel grade | Chemical composition% |
| C | Si | Mn | P | S |
| ST37.4/E235 | 0.07~0.13 | 0.17～0.37 | 0.35～0.65 | ≤0.035 | ≤0.035 |
| ST35 | 0.07~0.13 | 0.17～0.37 | 0.35～0.65 | ≤0.035 | ≤0.035 |
| ST45 | 0.17~0.23 | 0.17~0.37 | 0.35~0.65 | ≤0.035 | ≤0.035 |
| ST52/E355 | 0.13 〜0.19 | 0.20 〜0.60 | 1.20 〜1.60 | ≤0.030 | ≤0.030 |
Mechanical Property:
| Steel grade | Yield strength a | Tensile strength | Elongation |
| ReH | Rm | A |
| min. | min. | min. |
| MPa | MPa | % |
| ST37.4/E235 | ≥235 | 340 to 480 | ≥25 |
| ST35 | ≥235 | 340 to 480 | ≥25 |
| ST45 | ≥255 | 410 to 520 | ≥25 |
| ST52/E355 | ≥355 | 490 to 630 | ≥22 |
Tolerance：
| OD/mm | Tolerance/mm | ID/mm Tolerance/mm | Straightness/mm |
| 4~30 | ±0.08 | ±0.08~±0.15 | 0.1/1000 |
| 30~38 | ±0.15 | ±0.15~±0.20 |
| 38~50 | ±0.20 | ±0.20~±0.25 |
| 50~80 | ±0.25~±0.35 | ±0.25~±0.35 |