Technological and auxiliary materials when soldering

To technological materials when brazing are, components which are part of the formed brazed joints are solders and contact or barrier coatings.

Support materials include, components which are not directly included in generated brazed connections, but participating in its education. These include soldering fluxes, active and inert gas Wednesday, substances, limiting bleeding solder (stop materials), etc.


Pripoâm requirements:

1) Have a melting point below the melting temperature paâemyh metals.

2) Be familiar with metal paâemym coefficient of thermal expansion.

3) Be publicly available production technology and application.

4) At a temperature of soldering is well smaivat′ the base metal and fill gaps with connectors.

5) High strength of brazed joints.

6) Corrosion resistance of brazed joints.

7) Electrical conductivity.

8) Heat resistance.

Solders are divided into two groups- ready and from work (brazing).

Ready-made solders. The most widely used when soldering found ready-made solders. Ready-made solders is classified according to the following criteria (GOST 19250-73): largest of their temperature melting interval; the degree of melting when soldering; primary or most deficit component, ability to samoflûsovaniû; method of manufacturing and semi-finished products (rice. 6).

Temperature range of melting solder is the most important classification sign. Such a limited temperature interval start (solidus) and the end (Liquidus temperature) melting point solder. Largest thermal fusion interval, solders are divided into broad and solders with narrow crystallization interval. Ability to solder to scuff and zatekaniju into the gap, with its improved thermal melting interval. Solders with a narrow thermal melting interval badly kept in relatively extensive capillary gaps, but better asleep in narrow gaps. When brazing products with a large area or vertical sealing gaps with prior to laying in them it is better to use solder alloys with a wide thermal fusion interval, and when nekapillârnyh gaps-composite.

By the end of the melting temperature ready-made solders are divided into five classes:

- Osobolegkoplavkie -melting temperature less than 145° c;

- Fusible -melting temperature of 145° c to 450° c;

- Sredneplavkie -melting temperature of 450° c to 1100° c;

- Vysokoplavkie -melting temperature of 1100° С up to 1850° c;

- Refractory metals -melting point above 1850° c.

Classification of pre-made solder according to their autonomous melting. According to the degree of autonomous melting when brazing alloys are divided into fully and partially melting. Previously used mainly solders completely melting when soldering. The exceptions were solders, used in dental technology, and partially melting solders with wide intervals of hardening, who used mainly when abrasive brazing.

Classification of solder on the core component. Among metal solder, containing more than 50% one of the components of the, are Tin solders, cadmium, zinc, magnesium, aluminum, copper, cobalt, nickel, manganese, Gold, Palladium, Platinum, Titanium, iron, zirconium, niobium, molybdenum, vanadium, etc. If the content of certain components of the solders called on these core components, for example, Tin-lead, copper-nickel-manganese, etc. When the content of one or more of alloying components, are rare or precious metals, solder is sometimes referred to by these components, for example, Silver, Gold, etc., Although their content in solder may be a few percent.

Classification of solder on the ability to samoflûsovaniû. There are solders, that can also act as fluxes. Solders, possessing the properties of samoflûsovaniâ, must contain alloying elements-mixed with a strong chemical affinity to oxygen. These elements must contribute to the fluidity and wettability of solder metal paâemogo. Deoxidation products, from the interaction of such solder with paâemym metal, should easily be removed from the weld, in particular, to do this, the melting point of their soldering temperature must be below. To the elements-raskislitelâm include lithium, potassium, sodium, phosphorus, caesium, Bor, etc. Solders, alloy these elements and capable of samoflûsovaniû in inert gas or air Wednesday, referred to as samoflûsuûŝimi unlike other solders, When soldering fluxes are necessary, vacuum or active gas Wednesday.

Classification of solder on the way of manufacturing and semi-finished product. Manifold brazed construction and soldering methods, structural metals and solders with different properties and the need for their compatibility in production stimulated the development of different ways to manufacture semi-finished products solder. Traditional solders in the form of compact billets at many ways soldering and types of designs of modern products are not always comfortable. This was the widespread use of solder in the form of powders and pastes, tapes, shaped pressed and stamped blanks, as well as advance on brazed surfaces plated or termovakuumnym.

Solders, formed when soldering. This group includes contact reactive solders, the resulting in contact-Jet fusion paâemogo material with contact pads or coating or last among themselves; contact tverdogazovye solders, resulting from the melting of metal paâemogo, PIN cushions or coverings in pairs of metals or nonmetals, staying in the atmosphere furnace; reactive flux, resulting from displacement of metals from the Jet components fluxes.