English 
Français 
Deutsch 
Polski 
Italiano 
Español 
Soldering PasteS
Solder filler metals are defined as having a melting range below 450°C. They are typically broken into three main categories: lead-containing alloys, lead-free alloys, and low temperature alloys. Fusion solder paste alloys are designed to meet specific requirements for joining performance and melting range.
The following summarizes key properties of the various solder categories and the table below shows Fusion’s most common solder alloys:
| Fusion Solder Paste Alloys | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Industry Class | Fusion Number | Nominal Alloy Composition | Solidus Temperature |
Liquidus Temperature |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sn | Pb | Bi | Ag | Other | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Lead Free Alloys | 281 | 42 | – | 58 | – | – | 281°F | 138°C | 281°F | 138°C | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 425 | 91.8 | – | 4.8 | 3.4 | – | 410°F | 210°C | 425°F | 219°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 430 | 96.15 | – | – | 3.5 | 0.35 Sb* | 430°F | 221°C | 430°F | 221°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 431 | 96.5 | – | – | 3.5 | – | 430°F | 221°C | 430°F | 221°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 441 | 99 | – | – | – | 1 Cu | 440°F | 228°C | 440°F | 228°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 460 | 95 | – | – | – | 5 Sb | 452°F | 233°C | 464°F | 240°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 500 | 100 | – | – | – | – | 449°F | 231°C | 449°F | 231°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 505 | 94.65 | – | – | 5 | 0.35 Sb* | 430°F | 221°C | 473°F | 245°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Tin / Lead Alloys | 360 | 60 | 40 | – | – | 0.35 Sb* | 361°F | 183°C | 374°F | 190°C | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 361 | 62 | 36 | – | 2 | 0.35 Sb* | 354°F | 180°C | 354°F | 180°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 365 | 63 | 37 | – | – | 0.35 Sb* | 361°F | 183°C | 361°F | 183°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 450 | 50 | 50 | – | – | 0.35 Sb* | 361°F | 183°C | 421°F | 217°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 455 | 40 | 60 | – | – | 0.35 Sb* | 361°F | 183°C | 460°F | 238°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 560 | 5 | 93 | – | 2 | – | 530°F | 277°C | 568°F | 297°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 570 | 10 | 88 | – | 2 | – | 530°F | 277°C | 568°F | 297°C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
- Lead containing alloys are based on varying ratios of tin and lead, with common compositions including 60/40, 63/37, and 50/50. Tin/lead alloys have been widely used for decades due to their low melting points, excellent wetting properties, and reliability in creating strong and durable joints between metal surfaces. They exhibit good electrical conductivity, making them suitable for electronic soldering applications such as circuit board assembly and component connections. However, concerns about the environmental and health impacts of lead have led to the development and adoption of lead-free alternatives in many industries.
- Fusion lead-free alloys are typically based on tin and use various additives (silver, antimony, copper, bismuth) to increase strength and other physical properties. The most common alloys in this category are the tin-silver alloys, which exhibit better strength and improved creep resistance over the standard tin/lead series. Although requiring slightly higher soldering temperatures compared to traditional tin/lead alloys, Fusion Incorporated UK Ltd’s lead-free products have good capillary flow and offer excellent electrical conductivity. These are suitable for use in food-handling vessels where lead is prohibited. They also have a wide application range, from structural joining to electronics applications.
- Low-temperature alloys also known as fusible alloys, are specialized materials designed to melt at low temperatures compared to traditional metal alloys, and are typically based on bismuth and tin. With melting points below 150°C these alloys are commonly used in applications where lower processing temperatures are required or where heat-sensitive components are involved. They find use in various industries, including electronics, plumbing, model making, and prototyping. Low-temperature alloys offer advantages such as ease of use, good flow characteristics, and the ability to create intricate shapes or moulds. However, they may also have limitations such as reduced mechanical strength or susceptibility to environmental factors like corrosion. Careful consideration of the specific application requirements is necessary when selecting and using low-temperature alloys to ensure optimal performance and durability.