Steel SHY785
SHY785 is the higher-strength grade of the JIS G3128 quenched-and-tempered plate family, corresponding to the EN S890Q class.
Reference datasheet — SHY785 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the QT condition
SHY785 tempers and conditions
SHY785 is supplied in 5 conditions, soft to hard. QT is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Quenched, tempered and post-weld stress relieved | Condition of the finished weldment after SR annealing; expect a modest strength drop and slightly higher toughness. | 820 | 940 | 19 | 29 HRC | 7.2 % IACS |
QT | Use for thick penstock shells/branch pipes; mid-thickness properties fall slightly due to lower quench severity. | 820 | 950 | 17 | 29 HRC | 7.2 % IACS |
Q&T, low carbon-equivalent grade for improved weldability | Pick when field welding with reduced preheat is required; lower Ceq/Pcm at the same strength class. | 840 | 960 | 18 | 30 HRC | 7.3 % IACS |
Q&T grade qualified for post-weld stress-relief service | Choose for heavy weldments that must be PWHT/SR-annealed after fabrication without losing the 785 MPa yield class. | 845 | 960 | 18 | 30 HRC | 7.2 % IACS |
QTDefault Quenched and tempered | Standard mill-supplied condition for penstock and heavy welded structures up to ~50 mm thick. | 855 | 980 | 17 | 31 HRC | 7.2 % IACS |
What is SHY785?
SHY785 is the higher-strength grade of the JIS G3128 quenched-and-tempered plate family, corresponding to the EN S890Q class. The QT condition provides 855 MPa yield and 980 MPa tensile strength with 17 % elongation at about 300 HB (31 HRC), and plate is available in QT, QT-N, QT-NS, stress-relieved (QT+SR) and heavy-thickness (QT-THK) conditions for welded penstock and structural work. Welding demands tighter discipline than SHY685 — matching 780–890 MPa consumables, controlled preheat and limited heat input — and the steel has no corrosion resistance of its own. Use SHY685 (S690Q) where the extra yield is not required and fabrication is simpler. SHY785 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). SHY785 has a yield strength of 855 MPa (124 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 88% of steel grades. Elongation at break is 17% and the elastic modulus is 206 GPa (29.9 Msi).
What is SHY785 used for?
- penstocks
- pressure pipe structures
- heavy welded frames
Advantages
- High strength — 855 MPa (124 ksi), better than 88% of steel grades
Limitations
- Difficult to machine — 35/100, worse than 84% of steel grades
SHY785 properties
Typical room-temperature values for SHY785-QT; bars are the position among steel grades.
Physical3
SHY785 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
SHY785 has a yield strength of 855 MPa (124 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 88% of steel grades. Elongation at break is 17% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
SHY785 is rated for continuous service to 350°C (662 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
SHY785 conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of SHY785 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 25%.
Manufacturability5
SHY785's machinability is fair (35/100, worse than 84% of steel grades); weldability good (55/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. SHY785 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SHY785
Is SHY785 easy to machine?
Machine as a ~300 HB Q&T steel: rigid setup, coated carbide, moderate speed (60–110 m/min) and generous feed to stay below the work-hardened skin.
Can SHY785 be welded?
Weldable with low-hydrogen SMAW/FCAW/SAW consumables of matching 780–890 MPa class; use 100–150 °C preheat (higher for thick sections), control interpass ≤230 °C and limit heat input to protect HAZ toughness.
Can SHY785 be formed, bent or molded?
Cold bend with inside radius ≥3–4 t across the rolling direction; hot forming above the tempering temperature destroys the Q&T properties and requires re-heat-treatment.
SHY785 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 |
|---|---|---|
| Cladle analysis; low C for weldability | ≤ 0.18 | 0.14 |
| Si | 0.15 – 0.55 | 0.3 |
| Mn | 0.6 – 1.5 | 1.05 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.03 | 0.01 |
| Cuoptional | ≤ 0.5 | 0.2 |
| Nitoughness | 0.3 – 1.5 | 0.9 |
| Crhardenability | 0.3 – 1 | 0.55 |
| Motemper resistance | 0.2 – 0.7 | 0.45 |
| Voptional microalloy | 0.01 – 0.1 | 0.04 |
| Boptional, hardenability | 5×10⁻⁴ – 0.01 | 0 |
| CeqIIW carbon equivalent, thickness dependent | ≤ 0.62 | 0.56 |
| Fe | balance |
What surface finishes work on SHY785?
Blast-clean and apply epoxy/zinc-rich coating systems (penstock interiors) — the steel has no inherent corrosion resistance; avoid electroplating processes that risk hydrogen embrittlement at this strength.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SHY785 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- S890Q
How much does SHY785 cost?
SHY785 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SHY785 — frequently asked
What is SHY785 used for?
SHY785 is typically used for penstocks, pressure pipe structures and heavy welded frames. In short: 890 MPa-class structural plate; higher yield than SHY685; penstock-grade weldable steel.
What is the yield strength of SHY785?
SHY785 has a typical yield strength of 855 MPa (124 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 88% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is SHY785 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Machine as a ~300 HB Q&T steel: rigid setup, coated carbide, moderate speed (60–110 m/min) and generous feed to stay below the work-hardened skin.
Can SHY785 be welded?
Yes — weldability is rated good (55/100). Weldable with low-hydrogen SMAW/FCAW/SAW consumables of matching 780–890 MPa class; use 100–150 °C preheat (higher for thick sections), control interpass ≤230 °C and limit heat input to protect HAZ toughness.
What surface finishes work on SHY785?
Blast-clean and apply epoxy/zinc-rich coating systems (penstock interiors) — the steel has no inherent corrosion resistance; avoid electroplating processes that risk hydrogen embrittlement at this strength.
Can SHY785 be formed, bent or molded?
Cold bend with inside radius ≥3–4 t across the rolling direction; hot forming above the tempering temperature destroys the Q&T properties and requires re-heat-treatment.
What is the maximum service temperature of SHY785?
SHY785 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SHY785-QT and SHY785 QT-THK?
QT is the default condition — standard mill-supplied condition for penstock and heavy welded structures up to ~50 mm thick. QT-THK: use for thick penstock shells/branch pipes; mid-thickness properties fall slightly due to lower quench severity. Yield strength is 855 MPa in QT versus 820 MPa in QT-THK.
How much does SHY785 cost?
SHY785 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- JIS G3128 Higher yield strength steel plates for welded structure — JSA (2009)
- EN 10025-6 Hot rolled products of structural steels — Flat products of high yield strength structural steels in the quenched and tempered condition (S890Q) — CEN (2019)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19: Fatigue and Fracture — ASM International (1996)
- High-strength quenched and tempered plate datasheets (WEL-TEN / Q&T penstock plate class) — Japanese and Chinese plate mills (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.