Sandwich board is mada with two 0.5mm thick color steel sheets as top and bottom surface layers and close-hole fire-retardant polyrene foam board as middle layer and with special binder. It features light weight,high mechanical strength, heatinsulation, sound insulation, anticorrosiveness,steam resistance and weather resistance, etc, widely used as wall and roof boards of bulidings and in refrigerator.

Color coated steel sheet is made with coldrolled galvanized steel sheet as substrate, through surface deoiling, phosphating and chromating, etc, and through organic coating andbaking.

Tests prove that color sheet, heated with 120°C in baker for 96 hours, featuras consistent lusters and colors, without peeling when bent or punched. The coat layer is far more even, stable and better than shaped metal brush coating, and keeps bright without rusting for 15 to 20 years of properly maintenance in normal situation. This is a new kind of precoated steel product rapidly developing in the world, widely used in construction, household appliances and decoation industries, 36 kinds of colors are available now.

Maximum load under different height and thickness for each metre in width（kg/m）

	50	75	100	150	200	250
2.5	1534	2538	3557	5627	7715	9810
3.5	1210	2110	3065	5054	7094	9157
4.0	1066	1909	2821	4752	6754	8791
5.0	803	1553	2369	4155	6057	8021
5.5	735	1401	2166	3872	5713	7632
6.0	653	1266	1981	3603	5379	7246
7.5	469	944	1522	2894	4460	6152

Span(L) table （Maximum deflectinon £ < L/240）

	50	75	100	150	200	250
25	5.19	6.91	8.09	9.91	11.45	12.80
50	3.74	4.96	5.72	7.01	8.09	9.05
100	2.53	3.49	4.05	4.96	5.72	6.40
150	1.90	2.70	3.31	4.05	4.67	5.23
200	1.40	2.10	2.80	3.51	4.05	4.53
250	1.10	1.70	2.30	3.13	3.62	4.05
300	0.90	1.40	1.90	2.86	3.31	3.70

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