Consider the following statements in respect of oxy-acetylene welding:
1. The joint is not heated to a state of fusion.
2. No pressure is used
3. Oxygen is stored in steel cylinder at a pressure of 14 MPa
4. When there is an excess of acetylene used, there is a decided change in the appearance of flame.
Which of the statements given above are correct?
(a) 1, 2 and 3 (b) 2, 3 and 4
(c) 1, 3 and 4 (d) 1, 2 and 4