RTJ gasket full form

RTJ Gaskets are designed to seal by "initial line contact" or wedging action between the mating flange and the gasket. By applying pressure on the seal interface through bolt force, the softer metal of the gasket flows into the micro-fine structure of the harder flange material, creating a very tight and efficient seal.
Full form of RTJ gaskets are manufactured in accordance with API-6A and ASME B16.20 specifications and come in four basic forms:

R Oval vs Octagonal RTJ gaskets

Standard sizes of Style R RTJ gaskets are manufactured in accordance with both API 6A and ASME B16.20 size/ratings. Available in both oval and octagonal cross-section, both types are interchangeable on modern octagonal type grooved flanges.
Standard sizes of Style R RTJ gaskets can be manufactured in accordance with all relevant standards to suit the following flange designations: API-6A, ASME/ANSI B16.5, MSS SP44 (ASME B 16.47 Series A) & BS 1560. 
Type R-24 RTJ gasket size chart in mm

Ring number and material:	R-24,  Stainless Steel SS316
Weight:	0.38kg
Diameters(OD):	106.37 (+0.21,-0.19)
rtj gasket pitch diameter(PD2):	95.24 (+0.19,-0.17)
Thickness(H):	17.5 /16(±0.5) oval or octagonal configuration
Width(A):	11.14 (+0.19,-0.21)
Pipe and pressure application	2 inches, 900,1500 Class rating
Marking and identification:	04/22 Jayuseal R 24-S316

RX style form RTJ gaskets

Style RX RTJ gaskets are a pressure-energized adaptation of the standard Style R gasket. The RX is designed to fit the same groove design as a standard Style R, making the joints interchangeable. The modified form uses a pressure-energized effect that improves the efficiency of the seal as the internal pressure of the system increases.
Type RX-35 RTJ ring joint gasket dimension table in mm

Ring number and material	RX-35 , soft iron
Weight:	0.87 kgs
Diameters(OD):	147.29 (+0.45/-0.05)
Height of OD Bevel(D):	4.22 (+0.02/-0.78)
Thickness(H):	25.41 (+0.19/-0.01)
Width(A):	11.94 (+0.17/-0.03)
Flange and pipe application	3 1/8 inches, 5000 Class rating
identification Marking:	06/22 Jayuseal RX 35-D

BX form RTJ gaskets

Style BX ring joint pressure energized gaskets are manufactured in accordance with API 6A and are designed for use on pressurized systems up to 20,000 PSI. When correctly fitted, the BX form gasket allows virtual surface-to-surface contact of the flange faces, which means that the gasket is fully trapped on both the inner and outer diameters. All BX RTJ gaskets incorporate a pressure balance hole to ensure equalization of pressure that may be trapped in the grooves.
Type BX-155 RTJ ring joint gasket specification sheet in mm

Ring number,shape,material	BX155 rtj with drilling hole, low carbon steel
Weight:	0.66 kgs
Diameters(OD):	147.96 (0/-0.15)
Diameter of the flat (ODT):	145.95 (±0.05)
Thickness(H):	14.23 (+0.19/-0.01)
Width(A):	14.32 (+0.1/-0.1)
Pipe size and pressure application	4 1/16 inches, class rating 10000 to 20000
Identification	07/22 Jayuseal BX 155-S