SPHT 380-KS, STPT 370-JIS SMLS Pipe

SPHT 380-KS, STPT 370-JIS SMLS Pipe
STEELMAX Steel Story

주로 350℃ 이상에서 사용하는
Carbon steel for high temperature service 입니다.

KS D 3570에 SPHT 380, SPHT 420, SPHT 490,
JIS G 3456에 STPT 370, STPT 410, STPT 480,

각각 3가지 Grade가 있습니다.
Killed steel로만 제조 되며

SPHT490, STPT 480 은
SMLS로만 제조하도록 규정하고 있습니다.

350℃ 이하에서 사용하는 KS의 SPPS380, SPPS420,
JIS의 STPG 370, STPG410 압력 배관용 강관은

General 환경에서 사용되는 강관이며,
SPHT, STPT는 350℃ 이상에서 사용되는 강관과, 다릅니다.

수압 시험에서도 SPHT, STPT는 Schedule 160까지 규정된 강관으로
Schedule 80 까지만 규정된, SPPS, STPT와 다릅니다.

제조 방법에 따라
Seamless : S

Electric resistance welded : E
열간 생산이면 (Hot finished) : H

냉간 생산이면 (Cold finished) : C
강관 두께 표시인 Schedule에 따라 수압 시험 MPa가 달라집니다.

Steel Grade		KS D3570 SPHT380	KS D3570 SPHT420
Steel Grade		JIS G3456 STPT370	JIS G3456 STPT410
Chemical Composition (%)	Carbon (C)	0.25 max	0.30 max
	Silicon (Si)	0.10~0.35	0.10~0.35
	Manganese (Mn)	0.30~0.90	0.30~1.00
	Phosphorus (P)	0.035 max	0.035 max
	Sulfur (S)	0.035 max	0.035 max
Strength (N/㎟)	Yield	215 min (JIS)	245 min (JIS)
	Yield	220 min ㉿	250 min ㉿
	Tensile	370 min (JIS)	410 min (JIS)
	Tensile	380 min ㉿	420 min ㉿

Nominal wall thickness	Schedule number : Sch (Unit MPa)
	10	20	30	40	60	80	100	120	140	160
수압시험압력(min/MPa)	2.0	3.5	5.0	6.0	9.0	12	15	18	20	20

※ Killed Steel
Steel sufficiently deoxidized with ferrosilicon, aluminium, and so on.
In the case of ingot casting, during the progress of solidification in a ingot mold,
it is gently solidified without generation of carbon monoxide,
being comparatively uniform, with little segregation and has no blow hole.
however, because of a shrinkage cavity is formed in the centre of upper part,
its yield is low, In the case of continuous casting, it is killed steel and,
comparing with an ingot casting, uniformity and yield better.
killed steel is further classified according to grain size or deoxidizer.