Certificates

WYJ042-2005                                  638B

1, the technology conditions apply to manufacture the plastic mould parts with thickness is no more than the 400 mm the hardened 638 B alloy die steel plates.

2, size, shape, weight and allow deviation

2.1 the edge rolling steel together. Cut the head and tail, don't cut the sides.

2.2 steel plate roughness requirements: ≤7 mm/m;

2.3 plate thickness tolerance:-0 ~ + 3 mm;

2.4 the length of steel plate tolerance: + 20 ~ + 50 mm.

2.5 steel plate Flash cushion control (see table 1)

Table 1       unit ：mm

 

thick	Flash allowance
＜80	≥40
≥80～150	≥50
≥150～400	≥60

 

Note: the flash allowance for the sum of bilateral allowance.

2.6  weight and mark

Plates shall be ordered to theoretical weight delivery, steel plate width to steel plate, in three places the head, middle and tail of the width of the average minus the minimum allowance of steel for flash for weight width; Steel plate with the actual length length minus the minimum length for weight tolerance for length. "＜100 mm thickness steel plate, the added value of the thickness of 0.5 mm; 100 mm steel plate thickness frequency, the added value of the thickness of 1.0 mm. According to the regulations of the steel plate GB247 marking.

2.7 the rest of the steel plate size and shape, weight and deviation should be allowed to meet the provisions of GB709-88.

3, technical requirements

3.1 the chemical composition of the steel plate (melting analysis) shall conform to the provisions of table 2.

Table 2  wt%

 

composition	C	Si	Mn	P	S	Cr	Mo	Ni
technical requirements	0.34 ～ 0.42	0.30 ～ 0.60	1.00 ～ 1.50	≤0.030	≤0.020	1.80 ～ 2.40	0.20 ～ 0.40	0.15 ～ 0.25

3.2 delivery status: the hot rolling or tempering..

3.3 delivery hardness: 275 ~ 335 HB.