SK4 Special Steel Strip Blue Tempered Carbon Steel Coil

Hardened and tempered strip steel is our original and actual core business. Baomit production team properly harden and temper carbon steel strips to satisfy the most demanding specifications of different industries and customers. The strip steel has comprehensive mechanical properties with good strength, hardness and toughness.

Parameters	Recommendation
Steel Grade	SK4
Brand	BAOMIT
Certification	ISO9001:2015
Hardness	580 – 620 HV
Surface Finish	White polished, blue polished, yellow polished
Edges	Slit, square or round
Thickness Tolerance	+/- 0.005
Width Tolerance	+/- 0.10
Camber	Max 1mm per 3m

SK4 Special Steel Strip Blue Tempered Carbon Steel Coil

Our Advantages

• Excellent wear resistance

• Excellent punching and stamping properties

• Precise thickness and width tolerances

• Maximum straightness deviation of 1 mm / 3 m

• Good surface finish

• Consistent, specially adapted microstructure

Chemical Composition % of Steel SK4

C	Si	Mn	P	S	Cr	Ni	Cu
0.90-1.00	0.10-0.35	0.10-0.50	max 0.03	max 0.03	max 0.30	max 0.25	max 0.25

Thickness Tolerances

Thickness (mm)	Tolerances ± mm
Thickness (mm)	T1	T2	T3	T4	T5
0.020 - 0.040	0.004	0.003	0.002	-	-
0.040 - 0.100	0.006	0.005	0.004	0.003	0.002
0.100 - 0.125	0.007	0.005	0.004	0.003	0.002
0.125 - 0.160	0.009	0.006	0.005	0.004	0.003
0.160 - 0.200	0.010	0.007	0.005	0.004	0.003
0.200 - 0.250	0.011	0.008	0.006	0.004	0.003
0.250 - 0.400	0.015	0.011	0.008	0.006	0.004
0.400 - 0.600	0.020	0.014	0.010	0.007	0.005
0.600 - 0.800	0.023	0.017	0.012	0.008	0.006
0.800 - 1.000	0.027	0.019	0.013	0.009	0.007
1.000 - 1.250	0.034	0.024	0.017	0.012	0.008
1.250 - 1.600	0.039	0.028	0.020	-	-
1.600 - 1.750	0.046	0.033	0.023	-	-

Width Tolerances

Thickness (mm)	Width (mm)	Tolerances ± mm
Thickness (mm)	Width (mm)	W1	W2	W3
≤0.25	≤50	0.10	0.07	0.05
	50 - 125	0.15	0.11	0.07
	>125	0.20	0.15	0.10
0.25 - 0.50	≤50	0.15	0.11	0.07
	50 - 125	0.20	0.15	0.10
	>125	0.25	0.20	0.15
0.50 - 1.00	≤50	0.20	0.15	0.10
	50 - 125	0.25	0.20	0.15
	>125	0.30	0.25	0.15
1.00 - 1.60	≤50	0.20	0.15	0.10
	50 - 125	0.30	0.25	0.15
	>125	0.35	0.25	0.20
1.60 - 1.75	≤50	0.30	0.20	0.15
	50 - 125	0.35	0.30	0.20
	>125	0.40	0.30	0.20

Surface Roughness

Available in white polished, blue polished and yellow.

Thickness (mm)	Roughness
Thickness (mm)	Class 1	Class 2	Class 3
≤0.50	Ra≤ 0.30 µm Rt≤ 3.00 µm	Ra≤0.25 µm Rt≤ 2.50 µm	Ra≤ 0.20 µm Rt≤ 2.00 µm
0.50 - 1.00	Ra≤ 0.35 µm Rt≤ 3.50 µm	Ra≤ 0.25 µm Rt≤ 2.50 µm	Ra≤ 0.20 µm Rt≤ 2.00 µm
1.00 - 1.75	Ra≤ 0.40 µm Rt≤ 4.00 µm	Ra≤ 0.30 µm Rt≤ 3.00 µm	Ra≤ 0.30 µm Rt≤ 3.00 µm

Flatness Deviation

Maximum flatness deviation per inch strip width.

Thickness (mm)	Flatness Deviation
Thickness (mm)	Class 1	Class 2	Class 3	Class 4
0.02 - 0.10	P60	P50	P40	P30
0.10 - 0.25	P50	P40	P30	P20
0.25 - 0.50	P40	P30	P20	P10
0.50 - 1.75	P35	P25	P15	P10

Straightness Deviation

Strip Width (mm)	Measured Length (3m)
Strip Width (mm)	Class 1	Class 2	Class 3
≤50	3 mm	2 mm	1 mm
50 - 125	3 mm	2 mm	1 mm
>125	3 mm	2 mm	1 mm