Annealing is

Options

A. Heating steel in nitrogen and cooling
B. Heating steel to bright redness and then cooling slowly
C. Heating wrought iron with carbon to redness
D. Heating steel to high temperature and cooling suddenly by plunging in water

Answer

**Step-by-Step Solution:**

1. **Understanding Annealing**: Annealing is a heat treatment process used to alter the physical and sometimes chemical properties of a material. The primary purpose of annealing is to increase the ductility and reduce the hardness of a material, making it more workable.

2. **Heating Process**: The first step in the annealing process involves heating the steel to a specific temperature until it reaches a state of bright redness. This temperature is typically above the recrystallization temperature of the material.

3. **Cooling Process**: After the steel has been heated to the desired temperature, it is then cooled slowly. This slow cooling process allows the internal structure of the steel to rearrange, resulting in improved ductility and reduced hardness.

4. **Evaluating Options**:
- **Option 1**: Heating steel in nitrogen and cooling - Incorrect, as nitrogen is not involved in the traditional annealing process.
- **Option 2**: Heating steel to bright redness and then cooling slowly - Correct, as this describes the annealing process accurately.
- **Option 3**: Heating wrought iron with carbon to redness - Incorrect, as this does not describe annealing.
- **Option 4**: Heating steel to high temperature and cooling suddenly by plunging in water - Incorrect, as rapid cooling (quenching) leads to hardening, not softness.

5. **Conclusion**: Based on the evaluation of the options, the correct answer is **Option 2**: Heating steel to bright redness and then cooling slowly.

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