Pressure and temperature
The HT200 catalog covers 0.6 and 1.6 MPa with steam up to 220 °C. The cast-steel catalog extends to 6.4 MPa and steam up to 400 °C by pressure class.
How to match body material, complete trim, medium, temperature, pressure, and documentation to the governing standard.
The HT200 catalog covers 0.6 and 1.6 MPa with steam up to 220 °C. The cast-steel catalog extends to 6.4 MPa and steam up to 400 °C by pressure class.
HT200 valves are catalogued for seawater, freshwater, lubricating oil, fuel oil and steam up to 220 °C. GB/T 584 cast-steel valves are catalogued for freshwater, lubricating oil, fuel oil and steam up to 300 °C or 400 °C by pressure class.
Body material alone does not define the valve. Disc, seat, stem, seal, test records and certificate scope must be confirmed together.
The comparison below uses the two representative flanged stop-valve families already published on this website. It is not a statement that every HT200 or cast-steel valve has the same limits; the governing standard, body type, pressure class and project drawing remain decisive.
| Item | GB/T 590-2008 HT200 | GB/T 584-2008 ZG275-485 |
|---|---|---|
| Valve family | Marine cast-iron flanged stop valve | Marine cast-steel flanged stop valve |
| Body and bonnet | Gray cast iron HT200 | Cast steel ZG275-485 |
| Catalog pressure classes | 0.6 / 1.6 MPa | 1.0 / 1.6 / 2.5 / 4.0 / 6.4 MPa |
| Catalog size coverage | DN50-300, DN65-250 and DN20-50 by pressure and body type | DN65-300, DN65-250, DN20-150, DN65-100 and DN20-50 by pressure class |
| Catalog service media | Seawater, freshwater, lubricating oil, fuel oil and steam up to 220 °C | Freshwater, lubricating oil, fuel oil and steam up to 300 °C or 400 °C by pressure class |
| Representative disc / seat / stem | ZCuSn5Pb5Zn5 disc, ZCuA19Mn2 seat, CuA19Mn2 stem | Grade 20 disc, 2Cr13 stem, welded stainless-steel seal rings |
| Documentation | EN 10204 3.1 MTC, pressure-test records, inspection and class documents confirmed by product and order | Same confirmation basis; supplementary PMI or NDT when specified |
| Project condition | First catalogue reference | Why |
|---|---|---|
| Low-pressure seawater, freshwater or general service | GB/T 590 HT200 | The catalog directly lists seawater, freshwater and oil service at 0.6 / 1.6 MPa |
| Steam at 220 °C or below | GB/T 590 HT200 | Confirm the pressure class and cycling condition against the system design |
| Higher-pressure fuel or lubricating-oil line | GB/T 584 cast steel | The catalog covers pressure classes through 6.4 MPa with oil service |
| Steam at 300-400 °C | GB/T 584 cast steel | Catalog coverage reaches 400 °C, but only for the stated pressure and size combinations |
| A buyer-specified ASTM or class requirement | Technical confirmation | Do not infer substitution from material name alone; confirm grade, manufacturer scope and documents |
| Check | What to confirm | Risk if omitted |
|---|---|---|
| 1. Function | Stop, stop-check or other valve function | Material substitution cannot correct an incorrect valve function |
| 2. Design pressure | System pressure and catalog pressure class | An unavailable rating may be selected unknowingly |
| 3. Temperature | Maximum working temperature and cycling duty | Steam limits differ sharply between the two catalog families |
| 4. Medium | Actual medium and system location | Seawater, oil and steam place different demands on trim and sealing |
| 5. Complete material list | Body, bonnet, disc, seat, stem and seal materials | A body-only specification leaves the corrosion- and wear parts undefined |
| 6. Flange and dimensions | Drilling, face type, face-to-face and installation space | A stronger body material does not guarantee dimensional compatibility |
| 7. Documents | MTC, test records, inspection, PMI, NDT and class certificate | Late requirements may not match the production and inspection arrangement |
WCB is a common ASTM cast-steel reference in international procurement communication. The GB/T 584 catalog page on this site uses ZG275-485, so WCB should not be treated as automatic equivalence. Any alternative grade must be approved under the buyer specification, class requirement and manufacturer scope.
| Reference | Use in procurement communication | Caution |
|---|---|---|
| HT200 | Chinese gray-cast-iron grade listed for GB/T 590 body and bonnet | Confirm applicable pressure, temperature, media and class acceptance |
| ZG275-485 | Chinese cast-steel grade listed for GB/T 584 body and bonnet | Size and media coverage still depend on pressure class |
| ASTM WCB | Familiar reference for overseas buyers | Not an automatic substitute for ZG275-485 without technical approval |
Subject: Marine stop valve material review Valve function: stop / stop-check Reference standard: GB/T 590-2008 / GB/T 584-2008 / project standard Size and quantity: Design pressure: Maximum temperature: Medium and application system: Body / bonnet material: HT200 / ZG275-485 / specified alternative Disc, seat, stem and seal requirements: Flange drilling, face type and face-to-face: Classification society: Material certificate and pressure-test record requirement: PMI / NDT / third-party inspection requirement: Destination port and required date:
| Question | Answer |
|---|---|
| When should a marine valve use bronze, cast iron, cast steel, or forged steel? | Selection follows the governing standard, pressure, temperature, medium, cycling duty, corrosion requirement, and project approval. Bronze is common in seawater and smaller marine duties, cast iron is used within its pressure and temperature limits, cast steel covers higher pressure and temperature ranges, and forged steel is often used for smaller high-pressure duties. |
| Which body material is suitable for seawater, fuel oil, lubricating oil, freshwater, or steam? | Material suitability is confirmed by the product standard and complete material list, not by body material alone. For example, the GB/T 590 HT200 catalog includes seawater, freshwater, lubricating oil, fuel oil, and steam up to 220°C, while the GB/T 584 cast-steel catalog covers freshwater, lubricating oil, fuel oil, and steam up to 300°C or 400°C by pressure class. Compare HT200 and cast steel. |
| What is the difference between HT200 and cast steel for marine globe valves? | In the current catalog, GB/T 590 HT200 covers 0.6 and 1.6 MPa with steam up to 220°C. GB/T 584 cast steel ZG275-485 extends to 6.4 MPa and steam up to 400°C by pressure class. The complete trim, sealing, test, and document scope must still be confirmed. |
| What trim materials should be confirmed for steam service? | Confirm disc, seat, stem, seal ring, packing, gasket, and body/bonnet materials together with pressure, temperature, cycling duty, and the governing product standard. A body-only material callout does not define the wear, sealing, and temperature-critical parts. |
| What temperature limits must be checked before selection? | Check maximum working temperature, continuous and cyclic duty, saturation temperature for steam pressure, seat and seal limits, flange rating basis, and material-list suitability. Catalog temperature limits apply only to the stated standard, body type, size range, and pressure class. |
| Is cast steel always better than HT200? | No. Material selection follows the governing standard, pressure, temperature, medium, class requirement and project drawing. HT200 remains appropriate where its catalog coverage matches the service condition. |
| Can WCB replace ZG275-485? | Not automatically. WCB is a communication reference; approval depends on the buyer specification, class requirement, product scope and documentation. |
| Why does the same material have different limits? | Pressure and temperature limits apply to a specific standard, body type, size range and pressure class, not to the material name alone. |
| What should be sent with a material question? | Valve function, standard, size, design pressure, maximum temperature, medium, complete material requirement, flange details, class requirement and required documents. |
| Which documents are confirmed? | EN 10204 3.1 MTC, pressure-test records, inspection, PMI, NDT and classification-society documents are confirmed by product and order. |
This guide supports procurement communication and does not replace GB/T 590, GB/T 584, classification-society rules, the ship specification or the approved project drawing.
Send the service condition and project requirement. We will check the catalog coverage and documentation scope before quoting.