Dimensions of spectacle blinds according to ASME B16.48

Dimensions of spectacle blinds according to ASME B16.48 for installation between ASME B16.5 flanges.

Material Symbol	C	Mn	P	S	Si	Ni	Cr	Mo	Cu	N	V	Co
ASTM A105	0.35	0.60-1.05	0.035	0.04	0.10-0.35	0.4	0.3	0.12	0.4	_	0.08	_
ASTM A350 LF2	0.3	0.60-1.35	0.035	0.04	0.15-0.30	0.4	0.3	0.12	0.4	_	0.08	0.02
ASTM A182 F304	0.08	2	0.045	0.03	1	8.0-11.0	18.0-20.0	_	_	_	_	_
ASTM A182 F304L	0.03	2	0.045	0.03	1	8.0-13.0	18.0-20.0	_	_	_	_	_
ASTM A182 F316	0.08	2	0.045	0.03	1	10.0-14.0	16.0-18.0	2.00-3.00	_	_	_	_
ASTM A182 F316L	0.03	2	0.045	0.03	1	10.0-15.0	16.0-18.0	2.00-3.00	_	_	_	_
ASTM A182 F321	0.08	2	0.045	0.03	1	9.0-12.0	17.0-19.0	_	_	_	_	_
EN 10025 S235JR	0.2	1.4	0.045	0.045	_	_	_	_	_	0.01	_	_
20Mn	0.17-0.23	0.70-1.00	0.035	0.035	0.17-0.37	0.3	0.25		0.25
20	0.17-0.23	0.60-1.00	0.03	0.02	0.17-0.37	0.25	0.25		0.25
16Mn	0.13-0.19	1.20-1.60	0.03	0.02	0.20-0.60	0.3	0.3		0.25

Material Symbol	Tensile Strength, min, MPa	Yield point, min, Mpa	Elongation, min, %	Reduction of area, min, %	Hardness, max, HB	Min. Impact	Test Temperature, °C
ASTM A105	485	250	22	30	187
ASTM A350 LF2	485-655	250	22	30		20	-46
ASTM A182 F304	515	205	30	50
ASTM A182 F304L	485	170	30	50
ASTM A182 F316	515	205	30	50
ASTM A182 F316L	485	170	30	50
ASTM A182 F321	515	205	30	50
20Mn	450	275	24	50	197
20	410	245	25	55	156

Raised Face Joint Blanks

Raised Face Joint Blanks

• ASME B16.48 says: The gasket seating surface finish and dimensions for raised face line blanks shall be in accordance with ASME B16.5. A raised face may be specified at the option of the purchaser.
• A Raised Face would add machining time and complexity so the price would be higher. Call this the Bugatti or Rolls Royce of the line blind world.
• Personally, I have seen that version once or twice somewhere. The version without Raised Face is the default and is used everywhere.