Q235 carbon steel lap joint flange is one of material of carbon steel, we also has stainless steel and alloy steel. The lap joint flange also be called loose flanges,lap joint flange is often used in medium temperature and pressure are not high and the dielectric erosion is strong.
Lap Joint Flanges (LJ Flanges) ar used on piping fitted with lapped pipe or with splice stub ends the combined initial value of the 2 things being roughly tierce more than that of comparable attachment neck flanges.
Lap joint projection has 2 elements, a stub end, and a loose backing projection. Stub finish is butt welded to the pipe and Backing projection freely give way the pipe. The backing projection will be of various material than stub material and unremarkably of the steel to avoid wasting the price. Lap projection is employed wherever frequent disassembly is needed, and area is unnatural.

The splice projection is much a dead ringer for a wear projection except it’s a radius at the intersection of the bore and projection face.
The splice projection is much a dead ringer for a wear projection except it’s a radius at the intersection of the bore and projection face. This radius is critical to own the projection accommodate a splice stub finish. Normally, a splice projection associated a splice stub finish ar mated along is an assembly system.

Detail information of lap joint flange:
Size: 1/2” to 60”, DN 12mm to DN 1500m (and much larger size according to customers’ demands).
Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
Facing: RF / RT
Material:
Cabon steel: A105, A350 LF2
Stainless steel: A182 F304/F304L/F316/F316L/F321
Alloy steel: F11, F12
Packing: plywood case and plywood pallet
Standards, Dimensions & Weight
ASME/ANSI B16.5 Class 150 LJ / Class 300 / Class 600 /Class 900 / Class 1500 / Class 2500

We also has another type pipe flange:

Carbon steel blind flange	Stainless steel slip on flange	ASME carbon steel pipe flange	AWWA C207 steel flange	A105 carbon steel socket weld flange