Types of Solder Wires and Melting Point of Solder Wires

According to the chemical composition of the auxiliary, solder wire can be divided into rosin core solder wire, no-clean solder wire, solid core solder wire, weighted solder wire, single-core solder wire, three-core solder wire, water-soluble solder wire, aluminum solder wire, stainless steel solder wire, etc., and the role of different solder wires is different. The following editor will introduce the use of solder wire.

The role of solder wire The solder wire used in manual electronic component welding is composed of two parts: tin alloy and additives. When carrying out electronic soldering, the solder wire and the electric soldering iron cooperate with each other, the high-quality electric soldering iron can provide stable and continuous melting heat, the solder wire is added to the surface and gap of the electronic components as a filler metal, so that the electronic components can be fixed, is the main component of soldering, the composition of the solder wire is closely related to its quality, and will have an impact on the chemical, mechanical and physical properties of the solder wire. Solder wire without additives cannot be used for soldering electronic components, because it does not have wetting and expanding, spatter will occur when soldering, and solder joints are not well formed, and long-term studies have shown that the performance of additives will affect the soldering performance of solder wires.

The following are the uses of different types of solder wires:

<!--[if !supportLists]-->1.<!--[endif]-->Rosin type: suitable for electronic repair welding of electronic and related components, the residue after welding has high impedance, no leakage, can pass the high-voltage test, and is the most commonly used tin wire in the electronics industry.

<!--[if !supportLists]-->2.<!--[endif]-->No-clean type: It is suitable for PCB board repair welding with less residue, high insulation resistance, and clean board surface.

<!--[if !supportLists]-->3.<!--[endif]-->Nickel plating type: It is suitable for the welding of nickel materials, nickel-plated components, wires, terminals, sockets, lamp holders and other hard materials.

<!--[if !supportLists]-->4.<!--[endif]-->Welding type: suitable for welding seam filling processing of zinc alloy jewelry such as high-end watches, bracelets, bracelets, corsages, shoe flowers, hairpins, etc.

<!--[if !supportLists]-->5.<!--[endif]-->Special tin wire: suitable for welding stainless steel, zinc alloy, aluminum lamp heads, etc., this flux is not rosin type, and the residue after welding can be washed.

<!--[if !supportLists]-->6.<!--[endif]-->Solid solder wire: Solid solder wire does not contain flux and is suitable for special purposes such as fuses and metal pipe fittings.

Industry examples

(1) Heavy non-ferrous metal smelting industry: tin ore furnace pre-batching, tin ore fumigation; tin smelting, tin refining, tin ore fumigation, tin electrolysis;

(2) Electrical machinery and equipment manufacturing industry: tinning of wires and cables;

(3) Electronic and communication equipment manufacturing industry: circuit substrate sintering, component wave soldering, component manual soldering.

The melting point of solder wire The melting point of solder wire is 183 degrees. When the tin content is higher than 63%, the melting temperature rises and the strength decreases. When the tin content is less than 10%, the soldering strength is poor, the hair extensions are brittle, and the lubrication ability of the solder becomes poor. Eutectic solder is the most ideal, at the eutectic temperature, the solder directly changes from solid to liquid without going through a semi-liquid state. Eutectic solders have a lower melting temperature than non-eutectic solders, which reduces the possibility of damage to the soldered components. At the same time, because eutectic solder directly changes from liquid to solid, it also reduces the phenomenon of virtual soldering. Generally, the melting point of lead-free solder wire is high, about 227 °C, and the melting point of solder wire of different solder materials is not much different, so before using solder wire, you should first understand how high the temperature of the weldment can withstand, and then choose a lead-free solder wire with a suitable melting point. The following are several commonly used specifications of lead-free solder wire and their melting points on the market.

There is the melting point of lead solder wire

(1) The melting point of 63/37 solder wire is 183 °C.

(2) The melting point of 60/40 solder wire is 185°C - 190°C.

(3) The melting point of 55/45 solder wire is 187°C - 202°C.

(4) The melting point of 50/50 solder wire is 190°C - 216°C.

(5) The melting point of 45/55 solder wire is 192°C - 227°C.

(6) The melting point of 40/60 solder wire is 194°C - 238°C.

(7) The melting point of 35/65 solder wire is 198°C - 247°C.

(8) The melting point of 30/70 solder wire is 202°C - 256°C.

The melting point of lead-free solder wire

（1）Sn - Cu - Nimelting point of solder wire为225℃ - 227℃。

（2）Sn - Cu - Agmelting point of solder wire211℃ - 219℃。

（3）Sn - Bi - Agmelting point of solder wire205℃ - 208℃。

（4）Sn - Znmelting point of solder wire117℃ - 119℃。

（5）Sn - Cumelting point of solder wire220℃ - 222℃。

（6）Sn - Agmelting point of solder wire221℃。

The melting point of commonly used solder wire (1) Tin 99.3 copper 0.7, solder melting point of 227 °C, belongs to eutectic solder. (2) Tin 96.5, silver 3 copper 0.5, solder melting point of 218 °C, close to eutectic solder. (3) Tin 42 bismuth 58, solder melting point is 138 °C, eutectic solder. (4) Tin 91 zinc 9, the melting point of solder is 199 °C, it is eutectic solder. (5) Tin 5 zinc 95, melting point is 382 °C, eutectic solder. Key points for selecting solder wire When choosing a solder wire, there are several factors that need to be considered in addition to the melting point. The first is the material of the soldering object, different materials have different requirements for the type of solder wire, for example, nickel-plated solder wire is required for nickel materials and nickel-plated components on the surface, and special tin wire is required for stainless steel and zinc alloy. The second is the requirement for residues, if there are requirements for PCB board repair welding with less residues, high insulation resistance, and clean board surface, no-clean solder wire is a better choice; In the case of electronic repair soldering of electronics and related components, rosin solder wire is more suitable because of its high residue impedance, no leakage and can pass high-voltage tests.

In addition, the soldering environment will also affect the choice of solder wire. In some environments where cleanliness is critical, water-soluble solder wire may be preferred because the residue after soldering can be washed and can better meet environmental cleaning requirements. In addition, in large-scale production, such as circuit substrate sintering and component wave soldering in the electronics and communication equipment manufacturing industry, it is necessary to consider factors such as the cost of solder wire and the stability of supply.

Storage and custody of solder wire The storage and custody of solder wire is also very important. Since the additives in the solder wire may be affected by environmental factors, the solder wire should be stored in a dry, cool, ventilated environment away from direct sunlight. A humid environment may cause moisture on the solder wire, which in turn can affect its soldering performance. If the solder wire is wet, there may be problems such as unstable soldering and bubbles during soldering. At the same time, it is important to avoid contact with corrosive substances, such as acids, alkalis, and other chemicals, which may corrode the solder wire and make it unusable.

In the process of storage, it is also necessary to pay attention to the packaging protection of the solder wire, and try to maintain the integrity of its original packaging. If the packaging is damaged, the solder wire may be contaminated, which can affect the quality of the solder. For solder wire that has been stored for a long time, it is best to conduct a random inspection before use to ensure that its soldering performance meets the requirements.

The future development trend of solder wire With the continuous development of science and technology, the requirements for solder wire are also increasing. On the one hand, with the increasing awareness of environmental protection, the demand for lead-free solder wire will continue to grow. Although lead-free solder wire has a high melting point, it is increasingly favored by various industries due to its friendliness to the environment and human health. In the future, the performance of lead-free solder wire may be further optimized, such as reducing the melting point and increasing the solder strength.

On the other hand, with the development of electronic equipment in the direction of miniaturization and precision, the welding accuracy and quality requirements of solder wire are also getting higher and higher. This requires the development of finer and more stable solder wires to meet the soldering needs of small electronic components. At the same time, the development of intelligent production will also put forward new requirements for the supply and use of solder wire, such as the automatic supply of solder wire, precise control of welding amount, etc., so as to improve production efficiency and welding quality.

Key points for selecting solder wire When choosing a solder wire, there are several factors that need to be considered in addition to the melting point. The first is the material of the soldering object, different materials have different requirements for the type of solder wire, for example, nickel-plated solder wire is required for nickel materials and nickel-plated components on the surface, and special tin wire is required for stainless steel and zinc alloy. The second is the requirement for residues, if there are requirements for PCB board repair welding with less residues, high insulation resistance, and clean board surface, no-clean solder wire is a better choice; In the case of electronic repair soldering of electronics and related components, rosin solder wire is more suitable because of its high residue impedance, no leakage and can pass high-voltage tests.

In addition, the soldering environment will also affect the choice of solder wire. In some environments where cleanliness is critical, water-soluble solder wire may be preferred because the residue after soldering can be washed and can better meet environmental cleaning requirements. In addition, in large-scale production, such as circuit substrate sintering and component wave soldering in the electronics and communication equipment manufacturing industry, it is necessary to consider factors such as the cost of solder wire and the stability of supply.

Storage and custody of solder wire The storage and custody of solder wire is also very important. Since the additives in the solder wire may be affected by environmental factors, the solder wire should be stored in a dry, cool, ventilated environment away from direct sunlight. A humid environment may cause moisture on the solder wire, which in turn can affect its soldering performance. If the solder wire is wet, there may be problems such as unstable soldering and bubbles during soldering. At the same time, it is important to avoid contact with corrosive substances, such as acids, alkalis, and other chemicals, which may corrode the solder wire and make it unusable.

In the process of storage, it is also necessary to pay attention to the packaging protection of the solder wire, and try to maintain the integrity of its original packaging. If the packaging is damaged, the solder wire may be contaminated, which can affect the quality of the solder. For solder wire that has been stored for a long time, it is best to conduct a random inspection before use to ensure that its soldering performance meets the requirements.

The future development trend of solder wire With the continuous development of science and technology, the requirements for solder wire are also increasing. On the one hand, with the increasing awareness of environmental protection, the demand for lead-free solder wire will continue to grow. Although lead-free solder wire has a high melting point, it is increasingly favored by various industries due to its friendliness to the environment and human health. In the future, the performance of lead-free solder wire may be further optimized, such as reducing the melting point and increasing the solder strength.

On the other hand, with the development of electronic equipment in the direction of miniaturization and precision, the welding accuracy and quality requirements of solder wire are also getting higher and higher. This requires the development of finer and more stable solder wires to meet the soldering needs of small electronic components. At the same time, the development of intelligent production will also put forward new requirements for the supply and use of solder wire, such as the automatic supply of solder wire, precise control of welding amount, etc., so as to improve production efficiency and welding quality.