write it in computer not hand writing There are three classi

write it in computer not hand writing

There are three classification for steel used in structural fabrication shop

1.      Stock steel, mill order steel, warehouse steel-define each?

2.      What is the purpose of reaming? When is it required?

3.      When is drilling substituted for punching?

Solution

1. stock steel-Most metal produced by a steel mill or aluminium plant is formed (via rolling or extrusion) into long continuous strips of various size and shape. These strips are cut at regular intervals and allowed to cool, each segment becoming a piece of bar stock.

mil order steel-Steel is produced by Steel Mills and buying steel directly from a Mill eliminates any middleman. The steel in truckload amounts (20 to 24 tons per coil). The Mill’s lead-time is between 4 – 10 weeks depending on what the material is. Mills will supply only a limited range of sizes.

ware house steel-  service center providing processing services for production-ready steel to metal stampers, fabricators and manufacturers.

2. Reaming is a cutting operation with a multi-edged cutting tool which is constantly in action. It is applied to finish drilled holes accurately to required size with higher accuracy and with a good surface finish. Reaming offers the advantage that a greater number of holes can be produced with consistently good quality. This requires a cutting tool (the reamer) which

- has exactly the same diameter required,
- has an adequate edge profile (lead, straight/helical-fluted and taper reamers) and
- is well sharpened.

Reaming is done for a hole that has been exactly pre-machined (good true-running accuracy and sufficient machining allowance). .

Reaming is applied for fitting holes and taper holes.

3. when Speed, accuracy, versatility and cost are the criteria , drilling is used in place of punching as drilling can give more no. of holes per minute.