Flawless tube and tubesheet joints are necessary for shell and tube heat exchanger with high leakproof ability and durability. The presence of weld defects or improperly expanded tube-to-tubesheet joints in a system that mixes and transfers fluids can lead to several negative consequences on heat exchanger process. Achieving a high-quality assessment of fabricated tube-to-tube sheet joints based on international standards is highly demanded in this situation. There are studies assessing the mechanical and metallurgical characteristics of tube-to-tube sheet joints that only employ one welding technique; however, there aren't enough research on the utilizing multiple welding techniques.In the fabrication stage, a combination of gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW) was employed followed by light expansion and post weld heat treatment( PWHT). This combination welding technique was adopted to ensure high-quality welds and achieve the desired joint strength and integrity. The welding and tube expansion process successfully produced high-quality tube-to-tubesheet joints.Linear and circular indications representing the cracks were absent during liquid penetration test. The minimum leak path was greater than the two-third of tube wall thickness. The findings of this study provide strong evidence supporting the use of a combined GTAW and SMAW process for the fabrication of tube-to-tubesheet joints. The methodology and results in this article are beneficial for researchers and industrialists working the design, manufacturing, and operation of shell and tube heat exchangers.