SNB16, Bolting for High Temperature, Cr-Mo-V

SNB16 Bolting Materials for High Temperature
STEELMAX Steel Story

SNB16 은 고온용 합금강 볼트재입니다.
SNB16 은 JIS G 4107, KS D 3755 에 나타나는

SNB5, SNB7, SNB16 3종류 Steel Grade가 있습니다.
이 규격에서의 볼트재란 봉강 및 나사 가공을 하지 않은 봉강,

스터드 볼트를 가리키며, 주로 고온에서 사용되는
압력 용기 밸브, 프랜지 및 이음 쇠에 사용되는

합금강 볼트재에 대한 규정입니다.
Chrome-Molybdenum-Vanadium Steel 합금강으로 불립니다.

SNB16 강재는 Killed steel로 제조 되며
열간 압연 (Hot Rolling) 또는 열간 단조 (Hot Forging)로 제조하고

필요에 따라 절삭 (Cutting), 연삭 (Grinding), 냉간 인발 (Cold Drawing) 등의
냉간 가공 (Cold Working)을 하며, 선재 (Wire Rods)를 제외한 볼트재는

Normalizing-Tempering 또는 Quenching-Tempering하며
Tempering의 온도는 650℃ 이상으로 규정 되 있습니다.

SBN16 은 ASTM
A193-B16 과 대응 가능합니다.

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.

Normalizing — Heat treatment consisting of austenitizing followed by air cooling.
The purposes of this operation are to eliminate the influence of pre-working,
to render the crystal grains finder and to improve their mechanical properties.

Quenching — Operation which consists of cooling a ferrous products more rapidly then in still air.
The use of a term specifying the cooling condition is recommended, for example
air- blast quenching, water quenching, step quenching, etc.

Tempering — Heat treatment applied to a ferrous product, generally after quench hardening, or
another heat treatment to bring the properties to the required level, and

consisting of heating to specific temperature (＜Ac1 )and soaking one or more time,
following by cooling at an appropriate rate, Tempering generally leads to a

reduction in hardness but can, in certain cases,
cause an increase in hardness(refer to secondary hardening.

A193 specification for alloy-steel and stainless steel bolting for high-temperature or
high pressure service and other special purpose applications.

Steel Grade		SNB16	A193 B16
Chemical Composition (%)	Carbon (C)	0.36~0.44	0.36~0.37
	Silicon (Si)	0.20~0.35	0.15~0.35
	Manganese (Mn)	0.45~0.70	0.45~0.70
	Phosphorus (P)	0.040 max	0.035 max
	Sulfur (S)	0.040 max	0.040 max
	Chromium (Cr)	0.80~1.15	0.80~1.15
	Molybdenum (Mo)	0.50~0.65	0.50~0.65
	Vanadium (V)	0.25~0.35	0.25~0.35
	Aluminum (Al)	0.015 max	–
Yield Strength (N/㎟)	16≤D	725min	105 ksi
	16＜D≤100	655 min	95 ksi
	100＜D≤120	590 min	85 ksi
Tensile Strength (N/㎟)	16≤D	860 man	125 ksi
	16＜D≤100	760 min	110 ksi
	100＜D≤120	690 min	100 ksi
1 ksi = 6.9 Mpa (N/㎟)

Class	Symbol	Diameter	Reference
Class1	SNB5	D100 max	AISI501, ASTM A193 B5
Class2	SNB7	D120 max	AISI4140, 4142, 4145, ASTM A193 B7
Class3	SNB16	D180 max	ASTM A193 B16