cold-rolled steel pipe Standard: DIN 2391, EN10305-1, EN10305-4, BS 6323, ISO 8535 STEEL GRADE: ST30Si, ST30Al, ST35, ST37, ST37.4, ST45, ST52, ST52.4, etc DELIVERY CONDITIONS The tubes can be produced in the following delivery conditions: BK (+C) Cold finished/hard (cold finished as drawn). No heat treatment after the last cold forming process. BKW (+LC) Cold finished/soft (lightly cold worked) After the last heat treatment there is a light finishing pass (cold drawing). BKS (+SR) Cold finished/stress relieve annealed. After the final cold forming process the tubes are stress relieve annealed. GBK (+A) Annealed. After the final cold forming process the tubes are annealed in a controlled atmosphere. NBK (+N) Normalized. (Mainly focus on) After the final cold forming process the tubes are annealed above the upper transformation point in a controlled atmosphere. 2 SURFACE TREATMENTS 1. Bare Tube (No coating): Bright and smooth, Surface Roughness both inner and outer surface 0.2Ra Maximum for special requirement 2. Surface Coating A. Silver galvanized B. Yellow galvanized C. Olive green coated Layer thickness: 8-20um, Salty Spray Test: 48-150 hours 3. Black phosphate 3 APPLICATIONS 1. Automotive fields A. Fuel injection lines/nozzles B. CNG (Compressed Nature Gas) tube-- Burst pressure: 1307Bar, Working Pressure: around 350bar C. Drive transmission: Steering column elements D. Gear shafts, hand brake, front axles, airbag inflators, stabilizers, seat fasteners, front-wheel drive shafts 2. Hydraulic Fields A. Hydraulic circuits (HPL), pneumatic lines, and hydraulic suspension B. Hydraulic cylinders (HPZ) SIZES AND TOLERANCE
Chemical and Mechanical performance:
Table 1- Chemical composition | |
Steel Grade | C% | Si% | Mn% | P% | S% | AL% |
St30Al or E215 | ≤0.10 | ≤0.05 | ≤0.7 | ≤0.025 | ≤0.025 | ≥0.025 |
St35 or E235 | ≤0.17 | ≤0.35 | 0.4-1.2 | ≤0.025 | ≤0.025 | |
St45 or E255 | ≤0.21 | ≤0.35 | 0.4-1.1 | ≤0.025 | ≤0.025 | |
St52 or E355 | ≤0.22 | ≤0.55 | ≤1.6 | ≤0.025 | ≤0.025 | |
| Table 2 - Mechanical properties at room temperature | | |
Delivery condition | BK | BKW | GBK | NBK |
steel Grade | Rm Mpa (Min) | A %(Min) | Rm Mpa(Min) | A %(Min) | Rm Mpa(Min) | A %(Min) | Rm Mpa(Min) | ReH Mpa(Min) | A %(Min) |
St30Al or E215 | 430 | 8 | 380 | 12 | 280 | 30 | 290 to 430 | 215 | 30 |
St35 or E235 | 480 | 6 | 420 | 10 | 315 | 25 | 340 to 480 | 235 | 25 |
St45 or E255 | 580 | 5 | 520 | 8 | 390 | 21 | 440 to 570 | 255 | 21 |
St52 or E355 | 640 | 4 | 580 | 7 | 450 | 22 | 490 to 630 | 355 | 22 |
Processing:
Inspection:
Packing and delivery: