To ensure the dimensional accuracy of products, our rolling mills are equipped with automatic gauge control and roll gap symmetry systems. Any deviations in shape characteristics are measured to guarantee the dimensions of the products. Important characteristics for strip products are typically thickness, flatness and straightness.
Deviations from flatness could be in the form of waviness (like edge waves or internal buckles), coil set and cross bow. Standards for deviations in coil set and cross bow according to different tolerance classes are given in the tables.
| H/T condition | Cold-rolled condition | |
|---|---|---|
| P0 | No requirements | No requirements |
| P1 | 0.4 | 0.6 |
| P2 | 0.3 | 0.4 |
| P3 | 0.2 | 0.3 |
| P9 | Acc. to requirements | Acc. to requirements |
Hardened and tempered (H/T) strip in all tensile strengths and cold-rolled strip tensile strengths below 1100 MPa. Max. values for entire width range.
| Tolerance class |
Width < 20 mm
(0.8 in.) |
Width 20- < 50 mm (0.8- <2 in.)
|
Width > 50 mm
(> 2 in.) |
|||
|---|---|---|---|---|---|---|
| Cross bow1) |
Coil set2) | Cross bow1) |
Coil set2) | Cross bow1) |
Coil set2) | |
| P1 | 0.6 | 35 (1.38) | 0.8 | 35 (1.38) | - | 35 (1.38) |
| P2 | 0.4 | 20 (0.79) | 0.6 | 20 (0.79) | - | 20 (0.79) |
| P3 | 0.3 | 10 (0.39) | 0.4 | 10 (0.39) | - | 10 (0.39) |
1) % of width
2) mm/300 mm (in./11.8 in.)
Straightness
The figure below shows how deviation from straightness is defined.
The value in the table gives the deviation from straightness for length of 1 meter. Deviations from straightness can be determined for other lengths using the formula a=b x L2, where
a = the required deviation from straightness in mm for a given length, in meters
b = deviation from straightness according to the table
Conversion between two lengths, L1 and L2
| Width, mm (in.) |
Max out-of-straightness, mm (in.).
Length 1 m (3 ft) Tolerance class1) |
|||
|---|---|---|---|---|
| R1 | R2 | R3 | R4 | |
| 8- <20 (0.31- 0.79) | 5 (0.2) | 2 (0.079) | 1.5 (0.059) | 1 (0.039) |
| 20- <50 (.70- 1.97) | 3.5 (0.14) | 1.5 (0.059) | 1 (0.039) | 0.7 (0.028) |
| 50- <125 (1.97- 4.92) | 2.5 (0.098) | 1.25 (0.049) | 0.8 (0.031) | 0.5 (0.02) |
| 125- (4.92) | 2 (0.079) | 1 (0.039) | 0.5 (0.02) | 0.3 (0.02) |
1) R0 = no requirement
R9 = according to customer's specification
| Width, mm (in.) |
Max out-of-straightness, mm (in.)
Length 1 m (3 ft) Tolerance class1) |
|||
|---|---|---|---|---|
| R1 | R2 | R3 | R4 | |
| 8- <20 (0.31- 0.79) | 5 (0.2) | 2 (0.079) | 1.5 (0.059) | 1 (0.039) |
| 20- <50 (.70- 1.97) | 3.5 (0.14) | 1.5 (0.059) | 1 (0.039) | 0.7 (0.028) |
| 50- <125 (1.97- 4.92) | 2.5 (0.098) | 1.25 (0.049) | 0.8 (0.031) | 0.5 (0.02) |
| 125- (4.92) | 2 (0.079) | 1 (0.039) | 0.5 (0.02) | 0.3 (0.02) |
| Tensile strength 1100- 1800 MPa | ||||
| - < 8 (-0.31) | 7 (0.28) | 4 (0.16) | 2.5 (0.098) | - |
| 8- <20 (0.31- 0.79) | 5 (0.2) | 3 (0.12) | 2 (0.079) | - |
| 20- <50 (.70- 1.97) | 4 (0.16) | 2.5 (0.098) | 1.5 (0.059) | - |
| 50- <125 (1.97- 4.92) | 2.5 (0.098) | 1.5 (0.06) | 1.25 (0.049) | - |
| 125- (4.92) | 2 (0.079) | 1 (0.039) | 1 (0.039) | - |
| Tensile strength >1800 MPa | ||||
| - < 8 (-0.31) | 8 (0.31) | 5 (0.2) | 3 (0.12) | - |
| 8- <20 (0.31- 0.79) | 6 (0.24) | 4 (0.16) | 2.5 (0.098) | - |
| 20- <50 (.70- 1.97) | 5 (0.2) | 3 (0.12) | 2 (0.079) | - |
| 50- <125 (1.97- 4.92) | 3 (0.12) | 2 (0.079) | 1.5 (0.059) | - |
| 125- (4.92) | 2 (0.079) | 1.5 (0.059) | 1 (0.039) | - |