Kallvalsat

COLD ROLLED SHEET

MANUFACTURING PROCESS

Cold rolling is based on hot-rolled pickled strips. Strips pass through a number of roller pairs, and their thickness is reduced while the material is cold. The sheet then has to be annealed and skin-passed in order to achieve its desired properties. Cold-rolled sheet is manufactured in thicknesses of approx. 0.30 to 3.50 mm.

STEEL GRADES

Mild steel:
Used when forming and drawing properties are more important than important than tensile ones. Available in grades ranging from DC01 to DC06.
High-strength steel:
Offers great opportunities for weight savings.
Micro-alloyed:
Combines high strength and good plasticity. Its uniform tensile properties make it suitable for bending and flanging as well as simpler forms of drawing.
Dual phase steel:
Designated as DP (Dual Phase) and characterised by very good plasticity in combination with high strength. The steel has good work and bake hardenability, which means that its yield strength is given a major boost in connection with bending and drawing.
Rephos steel:
This is a phosphorus alloy (P) high-strength steel grade with very good deep drawing properties. The ultimate strength of the ready detail is obtained by means of work hardening during drawing.

MECHANICAL PROPERTIES — SOFT STEELS
EN 10 130	Yield strength R_e (N/mm²)	Tensile strength R_m (N/mm²)	Elongation% A₈₀min. (%)	r₉₀ min.	n_{90 min}
DC 01	140-280	270-410	28	–	–
DC 03	140-240	270-370	34	1,3	–
DC 04	140-210	270-350	38	1,6	0,18
DC 05	140-180	270-330	40	1,9	0,20
DC 06	120-170	270-330	41	r ≥ 1,8	n ≥ 0,22
Values are based on samples taken transversely to the direction of rolling.

MECHANICAL PROPERTIES — HIGH-STRENGTH MICRO-ALLOYED STEELS
EN 10 268	Yield strength Re_e min.-max. (N/mm²)	Tensile strength Rm_m min.-max. (N/mm²)	Elongation A₈₀ min. (%)	Bending diameter at bending 180°
HC 260 LA	260-330	350-430	26	0 x t
HC 300 LA	300-380	380-480	23	0 x t
HC 340 LA	340-420	410-510	21	0 x t
HC 380 LA	380-480	440-560	19	0,5 x t
HC 420 LA	420-520	470-590	17	0,5 x t
Values are based on samples taken transversely to the direction of rolling.

SURFACE

For cold-rolled sheet metal, there are two grades of surface quality and one classification of surface roughness.

SURFACE ACCORDING TO EN 10 130
Surface quality A	Small defects such as pores, minor scratches and light discolouration are permissible. Surface quality A is the most common one and is suitable for most purposes.
Surface quality B	One of the sides must be free from defects that can affect the appearance of a quality-varnished surface. The other side must, as a minimum, fulfil the requirements for surface quality A.

SURFACE APPEARANCE ACCORDING TO EN 10 130
Finish	Symbol	Surface roughness
Glossy	b	R_a ≤ 0,4 μm
Semi-gloss	g	R_a ≤ 0,9 μm
Standard	m	0,6 μm < R_a ≤ 1,9 μm
Raw	r	R_a > 1,6 μm

We offer by default standard surface quality A, surface appearance m and lightly oiled surface.

THICKNESS TOLERANCES, ACCORDING TO EN 10 131:

For steel grades with a specified min. yield strength <260.

Nominal thickness (mm)	Thickness tolerances for nominal width (mm)
Nominal thickness (mm)	≤ 1200	> 1200 ≤ 1500	> 1500
≥ 0,35 till ≤ 0,40	± 0,03	± 0,04	–
> 0,40 till ≤ 0,60	± 0,03	± 0,04	± 0,05
> 0,60 till ≤ 0,80	± 0,04	± 0,05	± 0,06
> 0,80 till ≤ 1,00	± 0,05	± 0,06	± 0,07
> 1,00 till ≤ 1,20	± 0,06	± 0,07	± 0,08
> 1,20 till ≤ 1,60	± 0,08	± 0,09	± 0,10
> 1,60 till ≤ 2,00	± 0,10	± 0,11	± 0,12
> 2,00 till ≤ 2,50	± 0,12	± 0,13	± 0,14
> 2,50 till ≤ 3,00	± 0,15	± 0,15	± 0,16
For yield strength ≥ 260 < 340 N/mm², tolerances are raised by approx. 20%. For yield strength ≥ 340 ≤ 420 N/mm², tolerances are raised by approx. 40%. Narrower tolerances are available at extra charge.

WIDTH TOLERANCES, ACCORDING TO EN 10 131:

Nominal thickness (mm)	Width tolerance
Nominal thickness (mm)	(roller edges)	(mm)
≤ 700 ≤ 1200	– 0	+4
> 1200 ≤ 1500	– 0	+5
> 1500 ≤ 2055	– 0	+6