Cold-rolled steel is essentially hot-rolled steel that has undergone further processing to increase its strength and strength-to-weight ratio. In cold rolling, the hot-rolled steel sheet is cooled at room temperature and then annealed or tempered.

Generally speaking, cold rolled steel can be processed or manufactured to tighter tolerances and provide a better overall surface finish than hot rolled steel, which provides a good basis for painting. Because of its convenient processing and beautiful surface, cold-rolled steel sheets are widely used in daily life fields such as automobiles, power products, and furniture.

Cold-rolled steel has better surface properties than hot-rolled steel, so it is usually used in applications that require more technical precision or higher aesthetics. In terms of physical properties, the hardness, tensile strength and deformation resistance of cold rolled steel are all added by work hardening.
However, due to the additional processing of cold rolled steel, its cost is higher, and it also generates internal stress in the material, which may lead to unpredictable curling if the stress is not relieved during cutting, grinding or welding.
Cold rolled steel sheets can be identified by the following characteristics:
1. Smoother and finer surface, smaller tribute tea.
2. With clear corners and better straightness.

S235 JR,S235 JRG2,S235 J0,S235 J2,
S275 JR,S275 J0,S275 J2,
S355 JR,S355 J0,S355 J2,S355 J2G3,S355 J2G4,S355 K2,S 355 K2G3,S355 K2G4
Q235,Q355

S355 J0：Structural grade S, minimum yield strength 355N/m㎡, J0 grade confirms that the steel passes the longitudinal direction at 0℃, 27Jcharry v notchShock test.
S355 J0+AR：Structural grade S, also with a yield strength of 355 N/m², but in rolled form.
S355 J0+N：Structural class S, also with a yield strength of 355N/m㎡, but supplied in normalized condition.
S355 is widely used in structural engineering and construction industry, and the workability of S355 J0 structural steel and marine steel plate is similar to that of low carbon steel, and it also has excellent weldability and good shock resistance.
Q235 steel plate has goodplasticity, toughness, weldability and certain strength, with good cold bending properties.
Q355 steel plate has good mechanical properties, welding properties, hot and cold processing properties and corrosion resistance, and can be used to manufacture welded structures with high loads such as ships, boilers, and bridges.

Unit weight (kg/piece)	Size (a×b)
Thickness (t) (mm)	914×1829mm (3′×6′)	914×2134mm (3′×7′)	1219×2438mm (4′×8′)
0.7	9.19	10.70	16.30
0.8	10.50	12.20	18.70
0.9	11.80	13.80	21.00
1.0	13.10	15.30	23.36
1.2	15.80	18.40	28.00
1.4	18.40	21.40	32.70
1.5	19.70	23.00	35.00
1.6	21.00	24.50	37.30
2.0	26.30	30.60	46.70

grade	The chemical composition is not greater than Max.(%)
	C	Si	Mn	P	S
Q235A	0.22	0.35	1.4	0.045	0.050
Q235B	0.20	0.35	1.4	0.045	0.045
Q235C	0.17	0.35	1.4	0.040	0.040
Q235D	0.17	0.35	1.4	0.035	0.035
Q355A	0.20	0.5	1.7	0.035	0.035
Q355B	0.20	0.5	1.7	0.035	0.035
Q355C	0.20	0.5	1.7	0.030	0.030
Q355D	0.18	0.5	1.7	0.030	0.025
Q355E	0.18	0.5	1.7	0.025	0.020

grade	The chemical composition is not greater than Max.(%)
	C			Si	Mn	P	S	N	Cu
	t≤16	16＜t≤40	t＞40
S275 JR	0.21	0.21	0.22	N/A	1.5	0.035	0.035	0.012	0.55
S275 J0	0.18	0.18	0.18	N/A	1.5	0.030	0.030	0.012	0.55
S275 J2	0.18	0.18	0.18	N/A	1.5	0.025	0.025	N/A	0.55
S355 JR	0.24	0.24	0.24	0.55	1.6	0.035	0.035	0.012	0.55
S355 J0	0.20	0.20	0.22	0.55	1.6	0.030	0.030	0.012	0.55
S355 J2	0.20	0.20	0.22	0.55	1.6	0.025	0.025	N/A	0.55
S450 J0	0.20	0.20	0.22	0.55	1.7	0.030	0.030	0.025	0.55

grade	Yield strength not less than Min. (N/mm²)			Tensile Strength (N/mm²)	Elongation not less than Min. (N/mm²)			Impact test
	t≤16	16≤t≤40	40≤t≤60		t≤40	40<t≤60	60<t≤100	Temperature (°C)	Energy Min. (J)
Q235A	235	225	215	375~500	26	25	24	N/A	N/A
Q235B	235	225	215	375~500	26	25	24	20	27
Q235C	235	225	215	375~500	26	25	24	0	27
Q235D	235	225	215	375~500	26	25	24	-20	27
Q355A	355	335	325	470~630	20	19	19	N/A	N/A
Q355B	355	335	325	470~630	20	19	19	20	34
Q355C	355	335	325	470~630	21	20	20	0	34
Q355D	355	335	325	470~630	21	20	20	-20	34
Q355E	355	335	325	470~630	21	20	20	-40	34

When thickness t=16

grade	Yield strength not less than Min.（N/mm²）	Tensile Strength (N/mm²)	Elongation not less than Min. (N/mm²)	Impact test
				Temperature (°C)	Energy Min. (J)
S275 JR	275	410~560	23	20	27
S275 J0	275	410~560		0	27
S275 J2	275	410~560	21	-20	27
S355 JR	355	470~630	22	20	27
S355 J0	355	470~630		0	27
S355 J2	355	470~630	20	-20	27
S450 J0	450	550~720	17	0	27