Abstract
The data base system for an effective use of the SH-CCT diagram for welding (CCT diagram) has been developed by the use of an interactive personal computer. The data base has memorized about 200 sheets of CCT diagrams and data for estimation of hardness and percentage of microstructures.
The characteristics of this CCT diagram data base system are as follows:
1) In order to be most effective, this system has following three procedures for the practical application of the data base.
i) Procedure I is the case of the estimation of CCT diagram, hardness, and percentage of microstructures for some steel that the user desires to investigate HAZ properties. The CCT diagram with similar composition for that steel is selected from the data base and displayed on a CRT. If there is no suitable CCT diagram in the data base, it is possible to display with overlapping two CCT diagrams of which the amount of one or two elements differ from that steel. The user can estimate the CCT diagram of that steel by the interpolation or extrapolation from overlapped CCT diagrams.
ii) Procedure II is the case of the study for the effect of alloying elements on CCT diagrams, hardness, and percentage of microstructures. When the user input the all composition ranges excepting the element under consideration, CCT diagram under the condition is selected from the data base.
iii) Procedure III is the case of the steel selection under the condition of the limited welding condition or study of the CCT characteristics. When the user feeds the critical cooling time ranges, CCT diagram corresponding to it is selected from data base.
2) Hardness and percentage of microstructures are estimated and displayed on a CRT, when CCT diagram is selected from the data base and cooling time (A3 to 500°C) is fed or a calculated weld thermal cycle is given.
It is considered that this CCT diagram data base system is very effective for the weldability evaluation, the steel selection, and the development of a steel by the use of above functions of the selection and displaying of CCT diagram.
