Soldering:
* Solder: A low-melting-point alloy, typically lead-tin or tin-silver, used for joining metals like copper or brass. Solder is melted and flowed into the joint, creating a strong bond.
* Flux: A chemical compound that cleans the surfaces of the metals being joined and prevents oxidation during soldering.
Brazing:
* Brazing filler metal: A higher melting point alloy, like brass or bronze, that fills the joint and creates a strong bond.
* Flux: Used for the same reasons as in soldering.
Welding:
* Welding rod: A filler metal that melts and fuses with the parent metals, creating a continuous, homogenous joint.
* Shielding gas: Used in certain welding processes to protect the weld from atmospheric contamination.
Other methods:
* Adhesives: Some strong adhesives can be used to bond metal surfaces, especially for non-structural applications.
* Mechanical fasteners: Bolts, screws, rivets, and other mechanical fasteners can be used to join metals together.
Choosing the right method:
The choice of method depends on factors like:
* Type of metals being joined: Different metals have different melting points and chemical properties.
* Strength required: Welding offers the highest strength, while soldering provides a weaker bond.
* Temperature resistance: Brazing offers higher temperature resistance than soldering.
* Appearance: Some methods, like brazing, may leave a visible joint.
Specific examples:
* Copper pipes: Soldering or brazing is commonly used for joining copper pipes.
* Steel pipes: Welding is often used for joining steel pipes, but other methods like brazing or mechanical fasteners may be employed depending on the application.
Therefore, there is no single "substance" used to join metals together, but rather a range of methods and materials depending on the specific needs of the application.
