The Transition Joint is a prefabricated, non-seperable, metallugically bonded joint used for field butt welding
of dissimilar metal piping components which are not weldable to each other. Typical metals include aluminum
to stainless steel for cryogenic applications. Reliability
Tube Turns Transition Joints
have been manufactured for over 40 years in pipe sizes ranging from 1/2" to 36" diameter and have been produced
from a variety of stainless steels (304, 304L, 316, 316L, 321, 347) and aluminum alloys (3003, 5082, 5083, 6061).
They are used to join stainless piping to aluminum piping for cryogenic services down to minus 320 deg F and are
installed in heat exchangers, liquefied gas storage tanks and transfer lines. They are used in many applications
for pressures ranging from full vacuum to in excess of 6,000 psi.
The construction of these Transition Joints utilizes flanges and lap joint stub ends in accordance with ASME\ANSI
dimensions that are proven to be reliable in all service conditions. These components are continuously seal welded
to a bimetallic ring to provide a leakproof joint. This bimetallic ring consists of a layer of type 304 stainless
steel and a layer of 1100 aluminum joined together by pressure welding to produce a strong, ductile solid-phase
bond. The flanges are then bolted together and the bolts tightened to a predetermined torque. The bolts and nuts
are then tack welded to provide a non-seperable unit. These joints are constructed in accordance with ASME B31.3
Chemical Plant and Petroleum Refinery Piping and ASME Boiler and Pressure Vessel Code, Section IX, Welding and
Two Designs Available
To meet the varied requirements of the cryogenic industry, Tube Turns
offers two types of aluminum/stainless steel Transition Joints. The Type "T" uses aluminum and stainless steel
flanges and the Type "K" uses all stainless steel flanges and an aluminum stub end. The Type "T" design is generally
a more economical design for systems using high strength aluminum alloys such as 6061-T6 whereas the Type "K" design
is usually more economical for higher pressure systems utilizing the lower strength alloys suh as 3003 and 5083.