Wichan Chuaiphan's research while affiliated with King Mongkut's University of Technology North Bangkok and other places

... For high heat input, and consequently slow cooling rate, the solidification time gets longer and thus the initial content of ferrite is high; however, the duration of the transformation δ → γ is prolonged, leading to a possible reduction in the primary ferrite content, caused by increased formation of austenite; instead, if the heat input is lowered, the cooling rate increases, resulting in a possible increase in the ferrite content. The balance between ferrite formation and its transformation into austenite leads to competing effects, as confirmed by experimental observations: some authors [24,71] agree with the described trend, while other authors have detected the opposite [76,77]. ...

... This variation in micro-hardness values can be ascribed to the higher volumetric ferrite fraction in the W1-WZ than W2-WZ. Ferrite generally possesses greater hardness than austenite, and therefore, a higher fraction of ferrite with smaller GS avg (as seen in Fig. 8a) resulted in increased micro-hardness ( Ref 20,34). When moving from WZ to the ASS side for both weldments, in UMZ, a slight increase in micro-hardness values was observed as compared to the WZ. ...

... However, it is worth noting that the elevated oxygen levels in this sample may lead to a greater occurrence of oxides than in other welding joints. According to the findings of Bansod et al [16], Chuaiphan and Srijaroenpramong [17], and Utu et al [53]. ...

... According to Chuaiphan et al [15] reducing the heat input during welding leads to decreased weld bead width, δ-ferrite content, shorter dendrite length, and narrower inter-dendrite spacing. Also, the welded material's hardness and ultimate tensile strength (UTS) increase. ...

... The S30408 austenitic stainless steels have the characteristics of excellent weldability, corrosion resistance, and comprehensive mechanical properties. They also have been widely used in various industrial fields, such as the machinery manufacturing of food, the medical equipment, the vehicles and the ships, also the aviation parts, as so on [1][2][3]. In the J o u r n a l P r e -p r o o f manufacturing process, the applications of S30408 are affected by the demands of highprecision workpieces and complex structures, which cannot be ignored. ...

... The heat transfer of solder includes many complex phenomena such as convection, radiation, heat conduction, and movement of liquid metal flow [60][61][62][63][64][65][66]. Understanding this process requires solving heat transfer differential equations using numerical methods such as finite differences or finite elements with computer software [67][68][69][70][71][72][73][74]. The heat transfer process here can be divided into two stages: the first stage considers the characteristics of the welding arc and the movement of particles in the liquid metal droplet from the moment of formation until impact with the bare metal; the second stage is the heat transfer process from the heat source (center of the weld) to the surrounding environment [75,76]. ...

... For both welding techniques, the width of the HAZ is seen to decrease in order to maximise welding speed. This is because, an increase in welding speed indications to decrease in heat input [50]. As the heat input reduces the cooling rate increases. ...

... Heat treatment results in a phase transition, which affects the mechanical characteristics of metals. Copper and zinc alloys' mechanical characteristics can be enhanced with heat treatment hardening at 780°C followed by water cooling [21]. Annealing increases the hardness and brittleness of Aluminum Bronze [22]. ...

... There are several methods for heating steel and processing it in a medium to extract heat from a specimen. Owing to the reasonable level of chromium and carbon in medium-carbon steel, hardening followed by tempering is regarded as the most typical heat treatment process (Rooprai et al., 2022;Ismail et al., 2016;Chuaiphan et al., 2013). ...

... 25 In the region of overpassivation, when the potential reaches a specific threshold, the passivation film on the metal surface is compromised, leading to pitting corrosion and a substantial escalation in the corrosion rate. 26 The passivation range of the welded joint has a noticeably smaller scope in comparison to that of the base material. Indicating that it is difficult to form a complete passivation film on welded joints under simulated pore fluid conditions. ...