A765 Plate with Mandatory Toughness Steel

A765 Plate with Mandatory Toughness Steel
STEELMAX Steel Story

A765, SA765는 의무 조항이 있는 압력용기용
저합금, 탄소강판에 대한 규정입니다.

인성 (Toughness)에 의무 조항이 있으며
A765, SA765 Grade 3 은 무려 -100℃에

Charpy V-Notch Impact Test 값이
요구되고 있는 강종입니다.

의무 조항이란, 해도 좋고, 안 해도 좋고가 아닌
꼭 해야 조항이고, , 그게 CVN을 하라는 겁니다.

A387, SA387 Specification covers heat-treated carbon steel and
alloy steel forging with mandatory toughness requirements.

These forgings are intended for pressure vessels,
feed-water heaters, and similar uses.

The degree of difficulty in occurring impact breaking
because of the material’s toughness.

※ Steels for pressure vessels
Steel products manufactured pressure vessels and high pressure
equipment which require strength, weldability and principally
toughness at a ordinary temperature.

※ Charpy impact test
Test to measure the absorbed energy, impact value, percentage
of brittle/ductile fracture, transition temperature, etc. with using
charpy impact testing machine in which test piece is supported by
two supports distant by 40 mm so that the notch meets the middle
between supports and is broken by striking with one blow of
pendulum to the face opposite the notch.

※ Steel forging
Steel ingot or semi-finished product to be wrought and formed to
provide a suitable wrought ratio and generally heat treated to
provide desired mechanical properties

※ Toughness (인성 : 靭性)
The degree of difficulty in occurring impact breaking
because of the material’s toughness .
질기고 세며, 충격 파괴를 일으키기 어려운지, 어떤지의 정도.

Steel Grade		A/SA765
Steel Grade		Gr.2	Gr.3	Gr.4
Chemical Composition (%)	Carbon (C)	0.30 max	0.20 max	0.20 max
	Manganese (Mn)	0.60~1.35	0.90 max	1.00~1.60
	Phosphorus (P)	0.020 max	0.020 max	0.020 max
	Sulfur (S)	0.020 max	0.020 max	0.020 max
	Silicon (Si)	0.15~0.35	0.15~0.35	0.15~0.50
	Nickel (Ni)	0.50 max	3.3~3.8	0.50 max
	Vanadium (V)	0.05 max	0.05 max	0.06 max
	Aluminum (Al)	0.05 max	0.05 max	0.05 max
	Chromium (Cr)	0.40 max	0.20 max	0.40 max
	Molybdenum (Mo)	0.10 max	0.06 max	0.10 max
	Copper (Cu)	0.35 max	0.35 max	0.35 max
Proof Stress (N/㎟)		250 min	260 min	345 min
Tensile Strength (N/㎟)		485~655	485~655	550~725
Elongation (min, %)		22	22	22
Reduction of area (min)		30	35	30
CVN of Average (min)		-45℃/20J	-100℃/20J	-30℃/35J