Exam 28: Weldability of Metals

The letter ____________________ in the AISI system, if used, indicate the manufacturing process electric furnace alloy steel.

Preheating is required any time that the metal to be welded is below 30 degrees F because the cold metal quenches the weld.

Since ____ stainless steels are not hardenable by quenching, the weld can be cooled using a chill plate.

____ cast iron is the hardest and most brittle of the cast irons because almost all of the carbon atoms are combined with the iron atoms.

Welding stresses occur because as metal is heated and cooled, it expands and contracts.

____ stainless steels are low in nickel. They are used in applications requiring both wear resistance and corrosion resistance.

A number of small welds are better than one or two large welds because the small welds do not have as much stress and are less likely to cause postweld cracking.

The ____ group of stainless steels is by far the most common.

In welding with the metal arc process, alternating current is more widely used than direct current.

____ cast iron is the most widely used type of cast iron. It is easily welded but because it is somewhat porous it can absorb oils into the surface, which must be baked out before welding.

Steels alloyed with carbon and only a low concentration of silicon and manganese are known as ____________________.

____________________ stainless steels can be much stronger than the austenitic, without losing toughness.

Preheating a part before starting the weld reduces the stress caused by the weld and helps the filler metal flow.

The lower the carbon content of the metal, the more difficult it is to weld the steel.

For steels containing more than ____ carbon, preheating and subsequent heat treatment are generally required to produce a satisfactory weld.

____ stainless steels are used for ornamental or decorative applications such as architectural trim and at elevated temperatures for heat exchanging.

The welding of ____ steels, having 0.30 to 0.50% carbon content, is best accomplished by the various fusion processes, depending upon the carbon content of the base metal.

The closer the characteristics of the deposited metal match those of the material being welded, the better is the corrosion resistance of the welded joint.

The major purpose of preheating and postheating of cast iron is to control the rate of temperature change.

The letter ____________________ in the AISI system, if used, indicate the manufacturing process basic open-hearth or electric furnace steel and basic oxygen furnace steel.