High-Temperature Solder Wire: Why Can It Withstand Secondary Reflow?

How can solder joints made with solder wire withstand secondary reflow heating without melting or falling off? This is a major challenge in the electronics and electrical manufacturing industry today. Many electronic engineers have conducted tests where, after soldering a board with standard lead-free solder wire, the original solder joints melted and components fell off during a second or subsequent reflow process. The issue is that the melting point of ordinary solder wire cannot withstand the 260°C environment of a reflow oven; the solder joints melt. The key lies in selecting a solder wire whose melting point can endure the high-temperature 260°C environment during the initial soldering. High-melting-point, heat-resistant solder wire provides a solution widely used in secondary reflow soldering processes.

Below, Singway's editors will explore just how high the melting point of high-temperature solder wire is, why it can withstand secondary reflow, and how its solder joints remain strong and reliable.

The melting point of ordinary 6337 leaded solder wire is 183°C, while common lead-free solder wire melts at 227-228°C. When the secondary reflow temperature reaches 260°C, if the melting point of the initial solder joint is below 260°C, the components will fall off as the solder joints melt during the second pass through the reflow oven.

High-temperature solder wire typically has a melting point above 255-265°C. When the soldered joint is exposed to the temperature of a secondary reflow oven for a very short time, the original joint can withstand the heat without melting. This allows it to endure the secondary reflow temperature, ensuring the solder joint remains secure and does not detach. High-temperature solder wire uses a special alloy formula and high-purity tin, giving it a melting point significantly higher than ordinary lead-free solder wire, while the secondary reflow temperature is generally below the melting point of this high-temperature wire, typically between 240-260°C.

Secondly, the solder joint itself is extremely strong. The joint formed after soldering has a fine crystalline structure and strong bonding force. Even after secondary high-temperature heating, issues like cold solder joints or detachment do not occur. These are advantages brought by optimized formulas and processes, which also reduce smoke and spatter during soldering and eliminate the need for additional cleaning afterward.

Therefore, the fundamental reason high-temperature solder wire can withstand secondary reflow is its high melting point, suitable for high-temperature environments, combined with its strong joints that resist secondary heating. Along with its environmentally friendly characteristics, it fully meets the requirements for secondary reflow soldering of electronic components.

When purchasing high-temperature solder wire, as long as you confirm the melting point and joint strength, you can solve the challenges of secondary reflow soldering, ensuring both production efficiency and improved product yield.

Singway, a manufacturer of high-temperature solder wire, produces high-temperature solder wire suitable for secondary reflow processes and can also customize products with melting points above 250°C according to specific requirements. If you are looking for a source supplier of high-temperature solder wire, please feel free to consult Singway Solder Wire.