The current search results do not mention the argon-helium ratio applicable to different titanium alloys. However, when choosing the argon-helium ratio, the following aspects can be considered comprehensively:
Consider alloy type
- α titanium alloy: This type of alloy has stable structure, higher wear resistance than pure titanium, strong oxidation resistance, but low room temperature strength. Because it is more sensitive to heat input during welding, the welding process needs to be precisely controlled. Generally, a higher proportion of argon can be used, such as 80%-90% argon and 10%-20% helium. A higher argon ratio helps stabilize the arc, accurately control the shape and size of the molten pool, reduce the heat-affected zone, and ensure the performance of the welded joint.
- α + β titanium alloy: It has good comprehensive properties, good structural stability, good toughness, plasticity and high-temperature deformation properties. The requirements for heat input during welding are relatively broad. Argon can account for 70%-80% and helium can account for 20%-30%. The addition of helium can appropriately increase the welding speed and penetration depth, while argon ensures the stability and protection effect of the arc.
- β titanium alloy: After heat treatment, the strength is higher, but the heat resistance is slightly worse, the volume mass is large, and the cost is high. A large heat input is required during welding to ensure the fusion quality. You can try to use argon gas at a ratio of 60% - 70% and helium gas at a ratio of 30% - 40%, and use the high energy characteristics of helium to increase the penetration depth and improve welding efficiency.
Combined with material thickness
- Thin plate titanium alloy: Thin titanium alloys are easy to deform during welding and require less heat input. For thin plate α, α + β or β titanium alloys, the argon ratio should be appropriately increased, such as argon gas accounting for more than 90%, and helium gas accounting for less than 10%, to reduce thermal effects and prevent deformation.
- Medium and thick plate titanium alloy: Medium and thick plate welding requires a greater penetration depth, and the proportion of helium can be appropriately increased. For medium and thick plates of α + β and β titanium alloys, the proportion of argon can be adjusted to 70% - 80%, and the proportion of helium can be 20% - 30%; for medium and thick plates of α titanium alloys, the proportion of argon can be around 80%, and the proportion of helium can be around 20%.
- Thick plate titanium alloy: Thick plate welding requires higher penetration depth, and the proportion of helium can be further increased. For thick plates of β titanium alloys, the proportion of argon can be reduced to 60%, and the proportion of helium can be increased to 40%; for thick plates of α + β titanium alloys, the proportion of argon can be 60% - 70%, and the proportion of helium can be 30% - 40%; for thick plates of α titanium alloys, the proportion of argon can be around 70%, and the proportion of helium can be around 30%.
Reference welding process and requirements
- Welding speed: If the welding speed needs to be increased, the proportion of helium can be appropriately increased. Because helium has high thermal conductivity, it can enable the welding area to obtain more heat, accelerate the formation and solidification of the molten pool, and thus increase the welding speed.
- Weld quality requirements: If the weld quality requirements are high, such as the weld surface is required to be smooth, without pores, cracks and other defects, the purity and appropriate proportion of argon should be guaranteed to provide good protection. At the same time, the proportion of helium should be fine-tuned according to the specific situation to optimize the welding parameters while ensuring quality.
