The purpose ofthis research was to create and find out the efficiency ofthe Computer Assisted Instruction (CAl) on the topic TIG Welding Process to the standard 90/90. And the learning achievement was analyzed after using this CAl The subjects used in this research were the second -year engineering students Industrial Technology Department the Faculty of Engineering at Rajamangala University of Technology Phra Nakhon who enrolled in this subject. The experiment started at the students did the pre test on the topic TIG Welding Process before they studied this lesson. Then they studied this lessonbyusingCALAfterthattheydidthepost -testonthistopicagain.Theresult ofbothtests was calculated to find out the efficiency of the CAl and analyzed the students learning achievement. The finding revealed that the efficiency ofthe CAl was efficient reached to the standard 90/90. In addition the students learning achievement was increased at significant level of 0.05 after using the CAl.

The purposes of the research were to create and find efticiency validation of computer assisted instruction focused on the fundamental of welding for the standard 90/90 and analyze the students learning achievement after using computer assisted instruction. The samples were the 20 first year Bachelor of Engineering Program in Industrial Engineering Rajamangala University of Technology Phra Nakhon. The researcher experimented by using pretest and then using the computer assisted instruction focus on the fundamental ofwelding and analyzed the students learning achievement after studying. The result revealed that the computer assisted instruction efficiency was efficient for standard 90/90. And after studying by using computer assisted instruction the students learning achievement increased significantly at 0.05.

This research is aimed at investigating the amount of chromium carbide (Cr23C6) in stainless steel AISI 304 by electrochemical technique testing in calculating the Pa values that corresponding to sensitization stage and the corrosion behavior. The results will carry on to developing the welding process. The specimens were produced with Shielded Metal Arc Welding method. Moreover it was bending at the angle 0 90 and 180 degree and the process finished on post-heat treatment with different cool down conditions are 800ºC annealed in air cooled 1100ºC annealed in water cooled and annealed 1100ºC in air cooled respectively. The results show that: first conditional is appeared the maximum amount of Pa value (Pa > 0.4) indicating that more precipitation of Cr23C6 in heat affected zone (HAZ) of specimen. The second conditional is not found the sensitization stage because when the specimens were annealed at high temperature the chromium carbide will break up and residual stress in HAZ will decrease. At last conditional is found the less amount of Pa value; the reason of using high temperature on annealing process will decrease chromium carbide but slowly air-induced cooling must pass the critical temperature then some Cr23C6 will appear at grain boundary and cause of high corrosion rate. Concerning to the corrosion behavior the second conditional present the lowest corrosion rate corresponding to the better-quality of passive film. Whereas the first conditional shown the highest corrosion rate and low quality of passive film. Thus 1100ºC annealed with water cooled is excellent condition for developing the welding process.

This research was to influence of electrode force affecting the complete of the resistance spot welding. The specimen was mild steel sheet metal has 1 mm. thickness. Then applied the force to the specimen are 1.0 2.0 3.0 4.0 and 5.0 kN. The welded specimens were tested by tensile shear testing according to JIS Z 3136: 1999 and Macro structure testing according to JIS Z 3139: 1978.The results showed that electrode force had affected on tensile shear and nugget size at 95% confidential (P value > 0.05). The low electrode force had increase the nugget heating because it had a high resistance (Q=I2Rt) and increase the gab between specimen. When the resistance increasing so the current flow will difficult to passed that fusion zone will had a high heating. It will affected to nugget seize heat affected zone and mechanical properties decreasing. The electrode forces are complete 2.0 kN. Tensile shear 6.39 kN and Nugget Size 5.83 mm. This data can be applied to be used as process monitoring of resistance spot weld quality.

The objectives of this research are to develop the welding process of copper tube for refrigeration in air conditioner by using rotation brazing table. The key design is the use of rotary head for nitrogen and rotary head for cooling water in assembly jig nitrogen discharge to prevent the internal welding soot to remove the soot that may occur during welding from piping system and to cool down the profile quickly. The result of water cooling to prevent that damage due to the heat of welding. The result from designing and creating of rotation brazing table to substitute stationary welding found that there is the reduction of machine cost by 11.61% or 46000 Baht/machine reduction of usage space 8.75 square meters or 74375 Baht increase of productivity by 93.48% reduction of nitrogen consumption by 98.20% or 2593 Baht/month reduction of support tool in production 75000 Baht per one rotation brazing table reduction of tiredness from working by 30.24% or equal to 137 manual works per day and reduction of usage of consumable material that can cause of greenhouse gas in form of trash such as cloth glove 1.40 KgCo2 per year leather glove 12.5216 KgCo2 per year nitrogen gas 0.1784 TonCo2 per year and water 0.54 KgCo2 per year. All of these can support the competition and dynamic change of industrial air conditioner in the future sustainably.