DH36 hot rolled steel sheet metal
DH36 steel is a high-strength structural steel grade primarily used in shipbuilding and marine applications. It falls under the category of low-carbon alloy steels, specifically designed to meet the stringent requirements of the marine environment. The primary alloying elements in DH36 steel include manganese, carbon, and silicon, which contribute to its overall strength, toughness, and weldability.
1 Comprehensive Overview
DH36 steel is classified as a structural steel grade that is particularly suitable for shipbuilding due to its excellent mechanical properties and resistance to harsh marine environments. The steel is characterized by its high yield strength, good ductility, and toughness, making it ideal for the construction of hulls and other structural components of ships.
The most significant characteristics of DH36 steel include:
High Strength: DH36 exhibits a minimum yield strength of 355 MPa (51.5 ksi) and a tensile strength ranging from 490 to 620 MPa (71 to 90 ksi).
Good Toughness: It maintains its toughness even at low temperatures, which is crucial for marine applications.
Weldability: The steel can be easily welded using conventional methods, which is essential for shipbuilding processes.
Advantages (Pros):
- Excellent mechanical properties that ensure structural integrity under dynamic loads.
- Good resistance to impact and fatigue, making it suitable for high-stress applications.
- Favorable weldability allows for efficient fabrication and repair.
Limitations (Cons):
- Limited corrosion resistance compared to higher alloyed stainless steels, necessitating protective coatings in certain environments.
- Not suitable for applications requiring extreme corrosion resistance or high-temperature performance.
Historically, DH36 steel has played a vital role in the shipbuilding industry, providing a reliable material for constructing vessels that must withstand the rigors of the sea.
2 Alternative Names, Standards, and Equivalents
| Standard Organization | Designation/Grade | Country/Region of Origin | Notes/Remarks |
|---|---|---|---|
| ASTM | DH36 | USA | Commonly used in shipbuilding |
| EN | S355G3 | Europe | Closest equivalent with minor compositional differences |
| JIS | SM490A | Japan | Similar properties but different standards |
| ISO | 6300-36 | International | General equivalent for structural applications |
The table above highlights various standards and equivalents for DH36 steel. Notably, while S355G3 and SM490A are often considered equivalent, they may have slight variations in chemical composition and mechanical properties that could affect performance in specific applications.
3 Key Properties
3.1 Chemical Composition
| Element (Symbol and Name) | Percentage Range (%) |
|---|---|
| C (Carbon) | 0.14 - 0.20 |
| Mn (Manganese) | 0.90 - 1.60 |
| Si (Silicon) | 0.10 - 0.50 |
| P (Phosphorus) | ≤ 0.025 |
| S (Sulfur) | ≤ 0.010 |
| Al (Aluminum) | ≤ 0.10 |
The primary alloying elements in DH36 steel play crucial roles:
- Carbon (C): Increases strength and hardness but can reduce ductility.
- Manganese (Mn): Enhances hardenability and toughness, improving the steel's performance in low-temperature environments.
- Silicon (Si): Improves deoxidation during steelmaking and contributes to strength.
3.2 Mechanical Properties
| Property | Condition/Temper | Test Temperature | Typical Value/Range (Metric) | Typical Value/Range (Imperial) | Reference Standard for Test Method |
|---|---|---|---|---|---|
| Yield Strength (0.2% offset) | Normalized | Room Temp | 355 MPa | 51.5 ksi | ASTM E8 |
| Tensile Strength | Normalized | Room Temp | 490 - 620 MPa | 71 - 90 ksi | ASTM E8 |
| Elongation | Normalized | Room Temp | ≥ 21% | ≥ 21% | ASTM E8 |
| Reduction of Area | Normalized | Room Temp | ≥ 30% | ≥ 30% | ASTM E8 |
| Hardness (Brinell) | Normalized | Room Temp | 170 - 210 HB | 170 - 210 HB | ASTM E10 |
| Impact Strength | Charpy V-notch | -20°C (-4°F) | ≥ 27 J | ≥ 20 ft-lbf | ASTM E23 |
The mechanical properties of DH36 steel make it suitable for applications that require high strength and toughness, particularly in marine environments where structural integrity is critical.
3.3 Physical Properties
| Property | Condition/Temperature | Value (Metric) | Value (Imperial) |
|---|---|---|---|
| Density | Room Temp | 7.85 g/cm³ | 0.284 lb/in³ |
| Melting Point | - | 1420 - 1460 °C | 2590 - 2660 °F |
| Thermal Conductivity | Room Temp | 50 W/m·K | 34.5 BTU·in/h·ft²·°F |
| Specific Heat Capacity | Room Temp | 460 J/kg·K | 0.11 BTU/lb·°F |
| Electrical Resistivity | Room Temp | 0.0000017 Ω·m | 0.0000017 Ω·ft |
Key physical properties such as density and melting point are significant for applications involving high temperatures and structural loads. The thermal conductivity indicates how well the material can dissipate heat, which is crucial in preventing overheating in marine engines.
3.4 Corrosion Resistance
| Corrosive Agent | Concentration (%) | Temperature (°C/°F) | Resistance Rating | Notes |
|---|---|---|---|---|
| Seawater | 3.5% | 25°C / 77°F | Fair | Risk of pitting |
| Sulfuric Acid | 10% | 25°C / 77°F | Poor | Not recommended |
| Chlorides | 5% | 25°C / 77°F | Fair | Susceptible to stress corrosion cracking |
DH36 steel exhibits moderate corrosion resistance, particularly in marine environments. While it performs adequately in seawater, it is susceptible to pitting and stress corrosion cracking in the presence of chlorides. Compared to higher alloyed stainless steels, DH36 requires protective coatings or cathodic protection to enhance its longevity in corrosive environments.
4 Heat Resistance
| Property/Limit | Temperature (°C) | Temperature (°F) | Remarks |
|---|---|---|---|
| Max Continuous Service Temp | 250°C | 482°F | Suitable for structural applications |
| Max Intermittent Service Temp | 300°C | 572°F | Short-term exposure only |
| Scaling Temperature | 500°C | 932°F | Risk of oxidation beyond this temp |
At elevated temperatures, DH36 steel maintains its structural integrity up to approximately 250°C (482°F). Beyond this, the risk of oxidation and scaling increases, which can compromise the material's performance in high-temperature applications.
5 Fabrication Properties
5.1 Weldability
| Welding Process | Recommended Filler Metal (AWS Classification) | Typical Shielding Gas/Flux | Notes |
|---|---|---|---|
| SMAW | E7018 | Argon/CO2 | Preheat recommended |
| GMAW | ER70S-6 | Argon/CO2 | Good penetration |
| FCAW | E71T-1 | CO2 | Suitable for thicker sections |
DH36 steel is highly weldable, making it ideal for shipbuilding applications. Preheating is often recommended to minimize the risk of cracking, particularly in thicker sections. The choice of filler metal can significantly influence the quality of the weld and the overall performance of the structure.
5.2 Machinability
| Machining Parameter | DH36 Steel | AISI 1212 | Notes/Tips |
|---|---|---|---|
| Relative Machinability Index | 60% | 100% | Moderate machinability |
| Typical Cutting Speed (Turning) | 30 m/min | 60 m/min | Use sharp tools and coolant |
DH36 steel has moderate machinability, which can be improved with proper tooling and cutting conditions. It is essential to use sharp tools and adequate cooling to prevent work hardening and tool wear.
5.3 Formability
DH36 steel exhibits good formability, allowing for both cold and hot forming processes. The material can be bent and shaped without significant risk of cracking, although care must be taken to avoid excessive work hardening. Typical bend radii should be determined based on the thickness of the material and the specific forming process used.
5.4 Heat Treatment
| Treatment Process | Temperature Range (°C/°F) | Typical Soaking Time | Cooling Method | Primary Purpose / Expected Result |
|---|---|---|---|---|
| Normalizing | 900 - 950 °C / 1652 - 1742 °F | 1 - 2 hours | Air | Refine grain structure |
| Quenching | 850 - 900 °C / 1562 - 1652 °F | 1 hour | Water/Oil | Increase hardness |
| Tempering | 500 - 600 °C / 932 - 1112 °F | 1 hour | Air | Reduce brittleness |
Heat treatment processes such as normalizing, quenching, and tempering are crucial for optimizing the mechanical properties of DH36 steel. Normalizing refines the grain structure, while quenching increases hardness. Tempering is essential to reduce brittleness and enhance toughness, particularly for applications subjected to dynamic loading.
6 Typical Applications and End Uses
| Industry/Sector | Specific Application Example | Key Steel Properties Utilized in this Application | Reason for Selection |
|---|---|---|---|
| Shipbuilding | Cargo Ships | High strength, toughness, weldability | Structural integrity under dynamic loads |
| Offshore Structures | Oil Rigs | Corrosion resistance, strength | Durability in harsh environments |
| Marine Engineering | Submarines | Low-temperature toughness, weldability | Safety and structural performance |
Other applications of DH36 steel include:
- Marine vessels: Used in the construction of various types of ships and boats.
- Floating structures: Employed in platforms and docks.
- Heavy machinery: Utilized in components that require high strength and durability.
The selection of DH36 steel for these applications is primarily due to its excellent mechanical properties and ability to withstand harsh marine conditions.
7 Important Considerations, Selection Criteria, and Further Insights
| Feature/Property | DH36 Steel | S355G3 | SM490A | Brief Pro/Con or Trade-off Note |
|---|---|---|---|---|
| Yield Strength | 355 MPa | 355 MPa | 345 MPa | Similar strength levels |
| Corrosion Resistance | Fair | Good | Fair | S355G3 offers better resistance |
| Weldability | Excellent | Good | Good | All grades are weldable |
| Machinability | Moderate | Good | Good | DH36 may require more effort |
| Formability | Good | Good | Good | All grades are formable |
| Approx. Relative Cost | Moderate | Moderate | Moderate | Cost is similar across grades |
| Typical Availability | High | Moderate | Moderate | DH36 is widely available |
When selecting DH36 steel, considerations include cost-effectiveness, availability, and specific performance requirements. While DH36 offers excellent mechanical properties, its corrosion resistance may not be sufficient for all applications, particularly in highly corrosive environments. In such cases, alternative grades like S355G3 or higher alloyed steels may be more appropriate.
In summary, DH36 steel is a versatile and robust material ideal for shipbuilding and marine applications. Its combination of strength, toughness, and weldability makes it a preferred choice, although careful consideration of its limitations and environmental factors is essential for optimal performance.
steel plates for shipbuilding Chemical Composition
| Grade |
C max |
Si max |
Mn |
P max |
S max |
Als min |
Ti max |
Cu max |
Cr |
Ni |
Mo |
Nb |
V |
|
DH36 |
0.18 |
0.50 |
0.90-1.60 |
0.035 |
0.035 |
0.015 |
0.02 |
0.35 |
0.20 |
0.40 |
0.08 |
0.02-0.05 |
0.05-0.10 |
dH36 steel plate mechanical property
| Grade |
Rm |
Re(MPa) min |
A% min |
Akv/J min |
||||||
|
DH36 |
490-630 |
355 |
21 |
E.T °C |
Thickness (mm) |
|||||
|
-20 |
≤ 50 |
>50-70 |
>70-100 |
|||||||
|
L |
C |
L |
C |
L |
C |
|||||
|
34 |
24 |
41 |
27 |
50 |
34 |
|||||
FAQ aBOUT DH36 marine grade steel plate
1.What is the difference between DH36 steel plate and D36 steel plate?
DH36 steel plate and D36 steel plate are different labeling methods of different classification societies, all of them are high strength marine steel. D36 steel plate is an American standard and DH36 steel plate is an international standard.
Marine steel plate refers to the hot-rolled steel plate which is manufactured for hull structure according to the requirements of Classification Society Construction Code. Because of the harsh working environment of the ship, the hull shell is subject to chemical corrosion, electrochemical corrosion and corrosion of marine organisms and microorganisms. The hull is subject to strong wind and wave impact. Therefore, the requirement of the ship plate is higher, which requires the certification of the classification society.
The general strength structural steels in China Classification Society Standards are classified into four quality grades: A, B, D and E; the high strength structural steels are classified into three strength grades and four quality grades: A32 A36 A40 D32 D36 D40 E32 E36 E40 F32 F36 F40; the U.S. standard medium and high strength ship plates are all with "H", such as AH32, AH36, AH40, DH32, DH36 steel plate, DH40, EH32, EH36, EH40, FH32, FH36 and FH40.
Among them, C, D and E grade steels have good low temperature toughness. It can be used in ships, boilers, pressure vessels, oil storage tanks, bridges, power plant equipment, lifting and transportation machinery and other welding structures with higher loads.
2.What is the difference between A36 and DH36 steel
Both A36 and DH36 steel are shipbuilding steel under ASTM A131/A131M. They have totally same chemical composition and strength.
The difference between A36 and DH36 steel chemical composition
| Grade | C | Si | Mn | P | S | Cu | Cr | Ni | Nb | V | Ti | Mo | Als |
| A36 | ≤0.18 | ≤0.50 | 0.90-1.60 | ≤0.035 | ≤0.035 | ≤0.30 | ≤0.20 | ≤0.40 | 0.02-0.05 | 0.05-0.10 | ≤0.02 | ≤0.08 | ≥0.015 |
| DH36 | ≤0.18 | ≤0.50 | 0.90-1.60 | ≤0.035 | ≤0.035 | ≤0.30 | ≤0.20 | ≤0.40 | 0.02-0.05 | 0.05-0.10 | ≤0.02 | ≤0.08 | ≥0.015 |
The difference between A36 and DH36 steel mechanical properties
| Grade | Tensile Test | Impact Energy KV2/J | ||||
| Yield Strength ReH/Mpa | Tensile Strength Rm/Mpa | Elongation A/% | Temperature ℃ | Longitudinal | Transverse | |
| A36 | ≥355 | 490-620 | ≥21 | 0 | ≥34 | ≥24 |
| DH36 | ≥355 | 490-600 | ≥21 | -20 | ≥34 | ≥24 |
From above tables, we find the impact temperature of A36 and DH36 steel is different. A36 steel do 0℃ impact test, while DH36 steel do -20℃impact test. Therefore, though both A36 and DH36 steel are shipbuilding steel, they are used under different environment. The DH36 steel do well in lower temperature working conditions.
3.What is the dh36 equivalent to s355?
Can dh36 steel grade be used in place of s355 steel grade? The dh36 is equivalent to the s355 grade. The s355 is a higher specification material than the ship building steel abs dh36 sheet.
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