Steel 20R TMCP
Supply condition
TMCP = thermomechanically controlled processed
Controlled-rolled plate giving normalized-like fine grain without a separate furnace cycle; good toughness with lower carbon equivalent.
Values for the TMCP condition
Other 20R tempers and conditions
20R is listed in 5 conditions; see the grade overview at 20R.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Normalized then stress-relieved / simulated PWHT | Condition for thick or heavily welded vessels requiring PWHT; slight strength drop must be allowed in design. | 255 | 445 | 33 | 120 HB | 10.8 % IACS |
Normalized | Mandatory for plate over ~36 mm and preferred where uniform fine grain and better low-temperature toughness are needed. | 265 | 455 | 32 | 125 HB | — |
Low-sulphur, Ca-treated HIC/wet-H₂S resistant plate | Choose for wet H₂S / sour service; S ≤ 0.003 %, inclusion-shape controlled and NACE TM0284 tested. | 265 | 450 | 33 | 125 HB | 10.8 % IACS |
ARDefault As hot-rolled plate | Standard stock condition for thin/medium 20R–Q245R vessel plate where no normalizing is required. | 275 | 460 | 30 | 130 HB | 10.8 % IACS |
TMCPThis page Thermomechanically controlled processed | Controlled-rolled plate giving normalized-like fine grain without a separate furnace cycle; good toughness with lower carbon equivalent. | 290 | 470 | 32 | 130 HB | 10.8 % IACS |
What is 20R TMCP?
20R TMCP is 20R supplied in the TMCP condition — controlled-rolled plate giving normalized-like fine grain without a separate furnace cycle; good toughness with lower carbon equivalent. 20R TMCP has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 88% of steel grades. Elongation at break is 32% and the elastic modulus is 206 GPa (29.9 Msi). 20R TMCP has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). AR is the default condition FabDigit quotes; TMCP is available on request or by drawing note.
Advantages
- Readily welded — 97/100, better than 100% of steel grades
- Tough — resists crack growth — 175 MPa·√m (159.3 ksi·√in), better than 98% of steel grades
- Forms and bends easily — 85/100, better than 96% of steel grades
- Ductile — tolerates forming and impact — 32%, better than 95% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
Limitations
- Low strength — 290 MPa (42.1 ksi), worse than 88% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
20R TMCP properties
Typical room-temperature values for 20R TMCP; 22 are specific to this condition. Other listed values are 20R reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20R TMCP has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
20R TMCP has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 88% of steel grades. Elongation at break is 32% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
20R TMCP is rated for continuous service to 400°C (752 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
20R TMCP conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 20R TMCP takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
20R TMCP's machinability is good (63/100, better than 92% of steel grades); weldability excellent (97/100); formability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20R TMCP
Is 20R easy to machine?
Machines like mild steel at ~65 % of AISI 1212; gummy chips in the as-rolled state, so use positive rake, good chip breakers and generous coolant.
Can 20R be welded?
Excellent weldability with CEV ≈ 0.35 — SMAW/SAW/GMAW with E7018 or F7A2-EM12K class consumables; preheat 100–150 °C above ~40 mm and PWHT at 600–640 °C per GB 150 when required.
Can 20R be formed, bent or molded?
Cold bends to 1.5×t radius; hot forming of heads at 900–1000 °C should be followed by normalizing if the finishing temperature is uncontrolled.
What surface finishes work on 20R?
No inherent corrosion resistance — shot-blast to Sa2½ and epoxy/zinc-rich prime, or use cladding/weld overlay/internal lining for wet service.
20R chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CGB/T 713 Q245R ≤0.20 | ≤ 0.2 | 0.17 |
| Si | ≤ 0.35 | 0.25 |
| Mn | 0.5 – 1 | 0.8 |
| P | ≤ 0.03 | 0.02 |
| S≤0.003 for HIC grade | ≤ 0.01 | 0.01 |
| Crresidual | ≤ 0.3 | 0.05 |
| Niresidual | ≤ 0.3 | 0.05 |
| Curesidual | ≤ 0.3 | 0.05 |
| Moresidual | ≤ 0.08 | 0.01 |
| Alsacid-soluble Al, fine-grain practice | ≥ 0.02 | 0.03 |
| Fe | balance | — |
20R TMCP — frequently asked
What is 20R TMCP used for?
20R TMCP is typically used for pressure vessel shells, storage tanks and process vessels. In short: workhorse vessel plate; HIC and Z35 options; best-value weldable plate.
What is the yield strength of 20R TMCP?
20R TMCP has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 88% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 20R TMCP easy to machine?
Reasonably — machinability is rated good (63/100, better than 92% of steel grades). Machines like mild steel at ~65 % of AISI 1212; gummy chips in the as-rolled state, so use positive rake, good chip breakers and generous coolant.
Can 20R TMCP be welded?
Yes — weldability is rated excellent (97/100). Excellent weldability with CEV ≈ 0.35 — SMAW/SAW/GMAW with E7018 or F7A2-EM12K class consumables; preheat 100–150 °C above ~40 mm and PWHT at 600–640 °C per GB 150 when required.
What surface finishes work on 20R TMCP?
No inherent corrosion resistance — shot-blast to Sa2½ and epoxy/zinc-rich prime, or use cladding/weld overlay/internal lining for wet service.
Can 20R TMCP be formed, bent or molded?
Cold bends to 1.5×t radius; hot forming of heads at 900–1000 °C should be followed by normalizing if the finishing temperature is uncontrolled.
What is the maximum service temperature of 20R TMCP?
20R TMCP is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20R-AR and 20R TMCP?
AR is the default condition — standard stock condition for thin/medium 20R–Q245R vessel plate where no normalizing is required. TMCP: controlled-rolled plate giving normalized-like fine grain without a separate furnace cycle; good toughness with lower carbon equivalent. Yield strength is 275 MPa in AR versus 290 MPa in TMCP.
Sources
- GB 6654 (20R, superseded) (1996)
- ASTM A516/A516M Pressure Vessel Plates, Carbon Steel — ASTM International (2021)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels — ASM International (1990)
- ASME BPVC Section II Part D — material properties tables — ASME (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.