HR Sheet (Hot Rolled Sheet)
HR sheet refers to Hot Rolled Steel Sheet. It is produced by rolling steel at a very high temperature (above the recrystallization temperature of steel, usually > 900°C). This makes the steel easier to form and shape. HR sheets generally have a rough surface finish, less dimensional accuracy compared to cold rolled sheets, but they are cheaper and suitable for structural and general-purpose applications.
Key Characteristics
- Produced at high temperature → coarse surface, scale formation.
- Thickness range: usually 1.6 mm to 20 mm (can go higher).
- Strength: relatively lower compared to cold rolled steel.
- Easy to weld, bend, and cut.
- Applications: construction, automobile chassis, railway tracks, shipbuilding, pipelines, fabrication works.
Different Types of HR Sheets
- Commercial HR Sheets (Mild Steel Hot Rolled Sheets)
- General-purpose quality.
- Used in fabrication, storage tanks, railway wagons, ducting, etc.
- Structural HR Sheets
- Higher strength and load-bearing capacity.
- Used in construction beams, bridges, building frames, and heavy structures.
- Boiler Quality HR Sheets
- Made for high-temperature and high-pressure applications.
- Used in boilers, pressure vessels, heat exchangers.
- High Tensile HR Sheets
- Improved mechanical properties, higher yield strength.
- Applications: crane booms, heavy vehicles, earthmoving machinery.
- Automotive HR Sheets
- Specifically made for automobile frames and components.
- Require controlled composition for strength + formability.
- Pipeline HR Sheets / API Grade
- Used in oil, gas, and water pipelines.
- High weldability, toughness, and resistance to cracking.
- Pickled & Oiled HR Sheets
- After hot rolling, sheets are pickled (acid treatment) to remove oxide scale, then oiled to prevent rusting.
- Smoother finish, better suited for further cold forming and coating.
Here’s a structured comparative table of HR sheets for easy reference:
Comparative Table of HR Sheets
| Type of HR Sheet | Typical Grade / Standard | Key Properties | Applications |
|---|---|---|---|
| Commercial HR Sheets | IS 1079, ASTM A36 | Soft, ductile, easy to weld and bend | General fabrication, storage tanks, ducts, wagons |
| Structural HR Sheets | IS 2062 (E250, E350, E410) | Higher strength, good load bearing | Construction beams, bridges, frames, heavy structures |
| Boiler Quality HR Sheets | IS 2002, ASTM A516 | Withstand high pressure & temperature, good toughness | Boilers, pressure vessels, heat exchangers |
| High Tensile HR Sheets | IS 2062 E450/E500, ASTM A572 | High yield strength, better wear resistance | Cranes, earthmoving machinery, mining equipment |
| Automotive HR Sheets | IS 1079 CRCA (for auto use), SAE grades | Controlled composition, good formability, weldability | Car frames, chassis, automotive components |
| Pipeline / API HR Sheets | API 5L (X42–X80), IS 3589 | High toughness, crack resistance, good weldability | Oil, gas, water pipelines |
| Pickled & Oiled HR Sheets | IS 1079 PO, ASTM A569 PO | Oxide layer removed, smoother surface, corrosion protected | Further cold rolling, painting, galvanizing, coating |
Here’s the expanded Industrial Selection Guide for HR Sheets with thickness range and surface finish details added:
HR Sheets – Comparative Industrial Guide
| Type of HR Sheet | Typical Grade / Standard | Thickness Range | Surface Finish | Key Properties | Applications |
|---|---|---|---|---|---|
| Commercial HR Sheets | IS 1079, ASTM A36 | 1.6 – 20 mm | Rough, mill scale | Soft, ductile, easy to weld/bend | General fabrication, storage tanks, ducts, wagons |
| Structural HR Sheets | IS 2062 (E250, E350, E410) | 4 – 40 mm | Rough, scale present | High strength, load bearing | Construction beams, bridges, building frames |
| Boiler Quality HR Sheets | IS 2002, ASTM A516 | 6 – 60 mm | Normal hot rolled | Withstand high pressure & temp, good toughness | Boilers, pressure vessels, heat exchangers |
| High Tensile HR Sheets | IS 2062 E450/E500, ASTM A572 | 6 – 50 mm | Normal hot rolled | High yield strength, wear resistance | Cranes, earthmoving, mining equipment |
| Automotive HR Sheets | IS 1079 (Auto Grades), SAE | 1.6 – 6 mm | Smoother than commercial HR, controlled surface | Good formability, weldability | Car frames, chassis, auto parts |
| Pipeline / API HR Sheets | API 5L (X42–X80), IS 3589 | 6 – 60 mm | Normal hot rolled | High toughness, crack resistance | Oil, gas, water pipelines |
| Pickled & Oiled HR Sheets | IS 1079 PO, ASTM A569 PO | 1.6 – 6 mm | Smooth, oxide removed, oiled | Better surface finish, corrosion protection | Cold rolling base, painting, galvanizing |
This table gives a quick selection reference based on:
- Thickness needs (thin sheets for automotive, thick plates for boilers/pipelines)
- Surface finish requirements (pickled & oiled for coating, rough for structural use)
- Strength & service conditions (commercial vs. high tensile vs. boiler quality).
References
Here are standard references you can use for HR sheets (Hot Rolled Steel Sheets):
Indian Standards (IS)
- IS 1079 – Hot rolled carbon steel sheet and strip (commercial & drawing quality).
- IS 2062 – Hot rolled medium and high tensile structural steel.
- IS 2002 – Steel plates for pressure vessels for intermediate and high temperature service including boilers.
- IS 3589 – Steel pipes for water and sewage (for HR plate used in pipes).
ASTM Standards (American Society for Testing & Materials)
- ASTM A36 / A36M – Standard specification for carbon structural steel.
- ASTM A569 – Standard specification for hot-rolled carbon steel sheet and strip (commercial quality).
- ASTM A1011 / A1011M – Hot-rolled carbon steel sheet and strip, high strength low alloy.
- ASTM A516 / A516M – Pressure vessel plates, carbon steel, for moderate and lower temperature service.
- ASTM A572 – High-strength low-alloy columbium-vanadium structural steel.
API Standards (American Petroleum Institute)
- API 5L – Specification for line pipe (X42–X80 grades, used for pipelines).
Other International Standards
- EN 10025 – Hot rolled products of structural steels (European Standard).
- JIS G 3101 – Rolled steels for general structure (Japanese Standard).
- DIN 17100 – Structural steel grades (German Standard).
