Type of Hot Rolling Mill
Prior to continuous casting technology, ingots were rolled to approximately 200 millimetres (7.9 in) thick in a slab or bloom mill. Blooms have a nominal square cross section, whereas slabs are rectangular in cross section.
Slabs are the feed material for hot strip mills or plate mills and blooms are rolled to billets in a billet mill or large sections in a structural mill.
The output from a strip mill is coiled and, subsequently, used as the feed for a cold rolling mill or used directly by fabricators. Billets, for re-rolling, are subsequently rolled in either a merchant, bar or rod mill.
Merchant or bar mills produce a variety of shaped products such as angles, channels, beams, rounds (long or coiled) and hexagons. Rounds less than 16 millimetres (0.63 in) in diameter are more efficiently rolled from billet in a rod mill.
Hot Rolling - Hot Rolling Process | Hot Rolling Application | Types of Hot Rolling Mill | Hot Rolled Steel Tube | History
Cold Rolling - Physical metallurgy | Degree of cold work | Cold Rolling Stainless Steel | Manufacturing Process
Foil rolling | Rolling Mill | Steel Mill | Production methods | Recycling of Steel | Modern Steelmaking | Contemporary Steel
Machining surface finish chart: Ra vs RMS
USA Ra(µm) |
USA Ra (Micro inch) |
USA RMS (Micro inch) |
Machining Finish Method |
50.0 |
2000 |
2200 |
The most coarse machining or good rough casting surfaces |
25.0 |
1000 |
1100 |
Machining marks very obvious. Rough turning, boring, planning, drilling |
12.5 |
500 |
550 |
Machining marks obvious. Normal turning, boring, planning, drilling, grinding |
8.00 |
320 |
352 |
Machining marks visible. Normal turning, boring, planning, drilling , grinding |
6.30 |
250 |
275 |
Machining marks visible. Normal turning, boring, planning, drilling , grinding |
5.00 |
200 |
220 |
Machining marks not obvious. But still visible. Normal turning, boring, planning, drilling, grinding. |
4.00 |
160 |
176 |
Machining marks not obvious. But still visible. Normal turning, boring, planning, drilling, grinding. |
3.20 |
125 |
137.5 |
Machining marks not obvious. But still visible. Normal turning, boring, planning, drilling, grinding. |
2.50 |
100 |
110 |
Machining marks blur, but direction obvious. Number controlled turning, boring, planning, drilling, grinding. |
2.00 |
80 |
88 |
Machining marks blur, but direction obvious. Number controlled turning, boring, planning, drilling, grinding. |
1.60 |
63 |
69.3 |
Machining marks blur, but direction obvious. Number controlled turning, boring, planning, drilling, grinding. |
1.25 |
50 |
55 |
Machining marks direction blur, but still visible. Number controlled turning, boring, planing, drilling, grinding. |
1.00 |
40 |
44 |
Machining marks direction blur, but still visible. Number controlled turning, boring, planing, drilling, grinding. |
0.80 |
32 |
35.2 |
Machining marks direction blur, but still visible. Number controlled turning, boring, planing, drilling, grinding. |
0.63 |
25 |
27.5 |
Machining marks direction blur. Reaming, grinding, boring, rolling. |
0.50 |
20 |
22 |
Machining marks direction blur. Reaming, grinding, boring, rolling. |
0.40 |
16 |
17.6 |
Machining marks direction blur. Reaming, grinding, boring, rolling. |
0.20 |
12.5 |
13.75 |
Machining marks direction invisible. Grinding, super machining |
0.20 |
10 |
11 |
Machining marks direction invisible. Grinding, super machining |
0.20 |
8 |
8.8 |
Machining marks direction invisible. Grinding, super machining |
0.10 |
4 |
4.4 |
Surface dark gloss. Surper machining |
Related References:
Type of Hot Rolling Mill
Hot rolled stainless steel Tube
Hot Rolled Steel Thickness Weight Table
Tolerance to EN 10058 for Hot Rolled Flat Stainless Steel Bar
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