Corten steel, also known as COR-TEN steel or weathering steel, is a low-alloy, high-strength exterior steel, a type of “weathering steel” that was developed to eliminate the need for paint and to form a stable rust-like Appearance, even after years of exposure to the influence of the climate. The new steel was named Cor (corrosion resistance) and ten (tensile strength) for its properties.
Weathering steel can be used for a wide range of structural applications. It is a common product in bridge construction due to its low maintenance cost. It is also popular in modern architecture where there is a great demand for aesthetic finishes for sculptural buildings and decorative panels.
In the initial stage of use, Corten steel is pale yellow. In general application environments, the color of the protective rust gradually changes from brown to a stable dark brown after one to two years. After that, there is no noticeable change in color, possibly a deeper dark brown.

1. Weather resistance
Because Corten steel is highly weather resistant, it can be used without painting. Not only does the unpainted application have the economic advantage of reducing repainting costs, it also provides aesthetic benefits associated with protecting the calming color of the rust layer. Weather resistance depends on the product grade and use environment, and the weather resistance of Corten steel is 4-8 times that of ordinary steel.

2. Solderability
Trace amounts of alloying elements such as copper (Cu) and chromate (Cr) are added to Corten steel to ensure high weather resistance, while the carbon content is reduced to provide proper weldability. Corten steel can be welded by hand welding, gas shielded welding or submerged arc welding. In addition, spot welding can also be used for thin thickness weathering steels.

3. Processability
Corten steel has similar processing properties (cold forming, hot forming and gas cutting) to ordinary steel of equal strength. For strip-rolled products, the axis is preferably bent transverse to the main rolling direction. For applications requiring higher formability, EN10155 compliant steels provide guaranteed variability.

Typical applications of weathering structural steel:
• Building exterior cladding, weather stripping　　　• Chimneys and other structures in flue gas conditions　　　• shipping tank
• freight container　　　　　　　　　• bridge　　　　　　　　　　　　　　• heat exchanger

ASTM
Corten-A	Corten-B
A588Gr.A	A588Gr.B	A588Gr.C
A242	A709 Gr.50W
ASME
SA588 Gr.A	SA588 Gr.B	SA588 Gr.C	SA588 Gr.K
SA871 Type I Gr.60	SA871 Type I Gr.65	SA871 Type II Gr.60
SA871 Type II Gr.65	SA871 Type III Gr.60	SA871 Type III Gr.65
EN
S235J2W	S355J2WP	S355J0W	S355J0WP
S355J2G1W	S355J2G2W	S355K2G1W	S355K2G2W
JIS
SPA-H	SMA400AW	SMA400BW	SMA490AW
SMA490BW	SMA490CW	SMA50AW	SMA50CP
UNI
Fe360DKI	Fe510C1KI	Fe510D1KI	Fe510C2KI
Fe510D2KI	WR50A	WR50B	WR50C
NFA
E24W4	E36WA3	E36WA4	E36WB3
E36WB4	WTSt37-3	WTSt52-3
GB
09CuPCrNi-A	Q235NH	Q355NH	Q355qC
Q355qD	Q345qE

The steel grades with the best weathering properties are S355JOWP, S355J2JOWP and Corten A. However, these steel grades have lower impact strength than other weathering steels due to the use of lin as an alloying element. These weathering steels are best suited for steel sheet construction where there is no risk of brittle fracture.

When the risk of brittle fracture has to be considered in the design due to high material thickness, low operating temperature or other reasons, other EN 10155 steels or Corten B are preferred. In this way, the impact strength requirements of hot-rolled steel can be agreed with those of general steel structures.

At temperatures above 540°C, S355J0WP, S355J2WP, Corten A and Corten B have significantly higher spalling resistance than general structural steels.

unit weight （kg/piece）	size（a x b）
thickness（t） (mm)	914 x 1829mm	914 x 2134mm	1219 x 2438mm	1524 x 3048mm	1524 x 6096mm	1829 x 6096mm	1829 x 7315mm	2438 x 6096mm
	( 3’x 6’)	( 3’x 7’)	( 4’x 8’)	( 5’x 10’)	( 5’x 20’)	( 6’x 20’)	( 6’x 24’)	( 8’x 20’)
6.0	78.74	91.97	139.98	218.79	437.57	525.15	630.16	700.00
8.0	105.00	122.50	186.64	291.72	583.43	700.19	840.21	933.34
9.0	118.13	137.81	209.97	328.18	656.36	787.72	945.24	1050.00
10.0	131.25	153.12	233.30	364.64	729.29	875.24	1050.26	1166.67
12.0	157.50	183.74	279.96	437.57	875.15	1050.29	1260.31	1400.00
14.0	183.72	214.36	326.61	510.50	1021.00	1225.34	1470.37	1633.34
15.0	196.88	229.68	349.94	546.97	1093.93	1312.66	1575.31	1750.01
16.0	210.00	244.99	373.27	583.43	1166.86	1400.39	1680.42	1866.67
19.0	249.38	290.93	443.26	692.82	1385.65	1662.96	1995.50	2216.67
20.0	262.50	306.24	466.59	729.29	1458.58	1750.48	2100.52	2333.34
22.0	288.75	336.86	513.25	802.22	1604.44	1925.53	2310.58	2566.68
25.0	328.13	382.80	583.24	911.61	1823.22	2188.11	2625.66	2916.68
30.0	393.75	459.36	699.89	1093.92	2187.87	2625.73	3150.78	3500.01