SA299 AN, Mn-Si Pressure Vessel Carbon Steel

강판 SA299 AN , Mn-Si Pressure Vessel Carbon Steel
STEELMAX Steel Story

압력용기용 Mn-Si, Carbon Steel 입니다.
SA299 Gr.A / A299 Gr.A는

항복강도 (Yield Strength) 1″ and under/min 290 MPa,
인장강도 (Tensile Strength) min 515~655 MPa,

Fully killed, Vacuum-degassed,
Fine-grain steel로 제조 되는 용접용 강판입니다.

50mm (2″) 까지는 As rolled 공급이 많으며
2″ 이상은 Normalizing or stress relieved 또는

두 가지 열처리를 하는 경우도 있으며
PWHT condition : 620℃ × 3.5hr 와 같은

PWHT 시험과 Z-Direction (C-Direction)
Charpy V-Notch Impact Test 조건이 있을 수도 있습니다.

Manganese은  강인성, 고장력강, 내마모강 합금 원소로
Boron 다음의 담금질성 향상 원소이면서

Cr 보다도 담금질성 향상 원소입니다.
적열 취성 (Hot Shortness) 방지 원소이기는 하지만

Weldability(용접성), Ductility(연성)을
저하시키는 원소이기도 합니다.

압력용기 규격 중 가장 범용적으로 사용된
SA516 강재의 Mn 상한치가 1.20%,

SA515 : 0.90%, SA387-11, SA387-22 : 0.65%이고,
대개의 탄소강에서 1.0% 미만 수준의 합금량을 감안하면

SA299 (25t 이상) 1.50%는,
비교적 높은 Mn 합금량 입니다.

※ Ductility (연성 : 延性)
The property of metals that enables them to be
mechanically deformed when cold, without fracture.
In steel, ductility is usually measured by elongation
and reduction of area is determined in a tensile test.

※ Stress Relief
Heating to a suitable temperature, holding long enough
to reduce residual stresses and than cooling slowly
enough to minimized the development of new residual stresses.
A heat treatment in which the lock-up stresses in a bar caused
by cold working are removed by heating the bar closed to but
below the lower limit of the critical temperature range,
or to approximately 100℉  below the tempering  temperature.

※ Fine Grain Steel
Steels which resist grain growth over a considerable temperature range,
when held at temperature for a reasonable length
of time as is customary in heat treatment of steel.

※ Grain Growth
During a heat treatment process grains can grow at elevated temperature.
Grain growth (increase in grain size) results in decrease of 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.
They are generally used for the principal portions of
pressure vessels.

※ Red shortness (적열 취성 : 赤熱脆性, 고온 취성)
The brittleness property generated within a temperature range of hot working
주로 황이 함량이 높은 경우 열간 작업 공정 중 강이 깨지는 현상을 말합니다.

SA299 AN, Mn-Si Pressure Vessel Carbon Steel