The characteristics of materials and the selection standards have been discussed in detail in the previous chapter. Below, the influence of materials on the welding process is illustrated with diagrams.

In the market, since there is a wide variety of tinplates used for can production, the factors affecting the welding process include not only the basic properties of the material (single cold-rolled CA, BA material, double cold-rolled DR material), but also the temper grade of the tinplate and the passivation condition of the surface. However, the most significant factor influencing welding is still the tin coating weight.

Fig. 3-46 Relationship between Tin Coating Weight and Contact Resistance

As shown in Fig. 3-46, when the welding wheel pressure is kept constant (50 dan), the lower the tin coating weight (≤1 g/m²), the greater the surface contact resistance, which makes welding more difficult.