Weld Shrinkage Study
Abstract
Inherent in the ship hull construction during assembly of interim products is weld shrinkage. Shipbuilder have recognized this fact and they realize the necessity of planning added material into the design phase to compensate for weld shrinkage. The traditional method to compensate for shrinkage has been to add excess material, usually 1" of material on two sides of a block, that would be trimmed at the erection stage. Normally, this 1" of material would be adequate to compensate for any weld shrinkage incurred during block assembly. It is however, a commitment to rework. Modern shipbuilders, employing New Construction Building Techniques, are attempting to eliminate this commitment to rework. By adding just enough material to compensate for weld shrinkage at each of the interim processes, a neat hull block can be built. In order to accomplish this task, extensive data gathering of shrinkage at each interim process must be conducted. Results of the data gathering will then be analyzed and shrinkage factors for each of the interim processes will be developed. These shrinkage factors will then be communicated to the Hull Engineering Department for inclusion into the detailed hull block design. Shrinkage factors for interim processes may vary from shipyard to shipyard due to facilities, welding equipment, joint design, welding sequence, ambient temperature, and type of material. Establishing and maintaining shrinkage factors is an investment shipyards make in improving productivity. Through this study, the process of deriving shrinkage factors will be identified; from the development of check sheets, to establishing checking procedures, data gathering, and the statistical analysis of data. Remembering that a variety of variables can effect the determination of a shrinkage factor, emphasis will be placed on the How to of the process.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1993
- Accession Number
- ADA457049
Entities
People
- David L. Malmquist
- R. E. Doersksen
Organizations
- National Steel and Shipbuilding Company