Pitting hole evaluation by active infrared thermography in stainless steel 304

Abstract

Nowadays, infrared thermography technique is widely use in an engineering study to inspect various types of problem. In this experiment, active infrared thermography method is applied to overcome the constraint locating pitted inside pipe. The main purpose of this experiment is to examine the location of pitted occur in the stainless steel 304 and at the same time to identify the transient effect on the pipe against the duration of time radiation exposed. This experiment uses two unit of spotlight as sources of heat to emit radiation energy to the surface of the pipe. A FLIR T640 thermography camera was used to record the thermal contrast of the pipe in real time using FLIR Tools+ software installs in the laptop. This experiment was tested at normal surrounding temperature. All of the temperature data is then interpreted into contour graph by using Microsoft Excel to see the defect area based on temperature distribution. Based on the result, the most significant temperature drops within highest gradient observed at cooling phase are within 7s, 2s and 1s interval for 10s, 20s and 30s of radiation exposure respectively. The time of the pitted to appear is related to the exposure time of the radiation. The finding of this experiment shows that short duration time of radiation exposure will give the longer time interval of significant gradient to appear. Therefore, this experiment proves that infrared thermography is one of the non-destructive testing methods that can be used in inspecting the pipeline.