joints the above embodiments are given only as examples grooves may be varied in size and location for instance axially oriented grooves may be positioned adjacent upset portions at which it is desired to reduce stresses or make them more uniform bending stresses at anticipated bending portions of the keel joint may be reduced by more gradual or tapered upset transition zones the design of the centralizer the outer surfaces thereof the position and type of stress grooves the width of the centralizer the length of the upset and length and type of transition zone are all tools that may be flexibly utilized as discussed hereinbefore to provide an improved keel joint the larger portions of the upsets shown above are generally cylindrical but could take other shapes as desired as may need coordination with shrink fitting of the centralizer and costs thereof accordingly the present invention provides shrink fit centralizer assemblies of various types which may are especially useful as stress joints for absorbing the high stresses associated with keel joints and other riser interconnections the invention relates to stress joints such as a keel joint having an upset with a centralizer that is shrink fitted to the upset portion of the keel joint the keel joint has an upset generally cylindrical which has tapered sections on the upper and lower ends thereof which in some embodiments gradually blend into the od of the pipe sections above and below the upset the foregoing disclosure and description of the invention is therefore illustrative and explanatory of a presently preferred embodiment of the invention and variations thereof and it will be appreciated by.