GM190 Cast Steel: Properties and Key Applications

GM190 Cast Steel is a specific grade of cast steel known for its unique properties and applications in various engineering fields. Classified as a medium-carbon alloy steel, GM190 typically contains a balanced mix of carbon, manganese, and silicon, which contribute to its mechanical strength and durability. The primary alloying elements in GM190 include:

• Carbon (C): Enhances hardness and strength.
• Manganese (Mn): Improves hardenability and tensile strength.
• Silicon (Si): Increases strength and resistance to oxidation.

Comprehensive Overview

GM190 Cast Steel is recognized for its excellent mechanical properties, making it suitable for a wide range of applications, particularly in the automotive and machinery sectors. Its notable characteristics include good weldability, high strength, and resistance to wear, which are essential for components subjected to mechanical stress.

The advantages of GM190 include:

• High Strength: Suitable for load-bearing applications.
• Good Weldability: Can be easily welded using standard techniques.
• Wear Resistance: Ideal for components that experience friction.

However, GM190 also has limitations:

• Corrosion Resistance: Not as resistant to corrosion as stainless steels.
• Brittleness: Can become brittle if not properly heat-treated.

Historically, GM190 has been used in various applications, including structural components, automotive parts, and machinery, due to its favorable balance of strength and ductility.

Alternative Names, Standards, and Equivalents

Standard Organization	Designation/Grade	Country/Region of Origin	Notes/Remarks
UNS	G19000	USA	Closest equivalent to ASTM A216 WCB
ASTM	A216 WCB	USA	Commonly used for castings
EN	1.0619	Europe	Minor compositional differences
DIN	1.0619	Germany	Similar properties to GM190
JIS	G3106 SM490	Japan	Comparable in strength

The equivalent grades listed above may have subtle differences in composition and properties that can affect performance in specific applications. For instance, while ASTM A216 WCB is similar in strength, it may not perform as well in high-temperature applications compared to GM190.

Key Properties

Chemical Composition

Element (Symbol and Name)	Percentage Range (%)
C (Carbon)	0.20 - 0.25
Mn (Manganese)	0.60 - 0.90
Si (Silicon)	0.15 - 0.40
P (Phosphorus)	≤ 0.035
S (Sulfur)	≤ 0.035

The primary role of key alloying elements in GM190 includes:

• Carbon: Increases hardness and strength, essential for load-bearing applications.
• Manganese: Enhances hardenability, allowing for better performance under stress.
• Silicon: Improves oxidation resistance, contributing to the steel's durability.

Mechanical Properties

Property	Condition/Temper	Test Temperature	Typical Value/Range (Metric)	Typical Value/Range (Imperial)	Reference Standard for Test Method
Tensile Strength	Annealed	Room Temp	370 - 490 MPa	54 - 71 ksi	ASTM E8
Yield Strength (0.2% offset)	Annealed	Room Temp	220 - 300 MPa	32 - 44 ksi	ASTM E8
Elongation	Annealed	Room Temp	20 - 25%	20 - 25%	ASTM E8
Hardness (Brinell)	Annealed	Room Temp	150 - 200 HB	150 - 200 HB	ASTM E10
Impact Strength	Charpy, -20°C	-20°C	27 - 35 J	20 - 26 ft-lbf	ASTM E23

The combination of these mechanical properties makes GM190 suitable for applications requiring high strength and toughness, such as structural components and machinery parts.

Physical Properties

Property	Condition/Temperature	Value (Metric)	Value (Imperial)
Density	Room Temp	7.85 g/cm³	0.284 lb/in³
Melting Point	-	1425 - 1540 °C	2600 - 2800 °F
Thermal Conductivity	Room Temp	50 W/m·K	34.5 BTU·in/(hr·ft²·°F)
Specific Heat Capacity	Room Temp	0.46 kJ/kg·K	0.11 BTU/lb·°F
Electrical Resistivity	Room Temp	0.0000017 Ω·m	0.0000017 Ω·in

Key physical properties such as density and melting point are significant for applications where weight and thermal management are critical. The density provides insights into the material's weight, while the melting point indicates its suitability for high-temperature applications.

Corrosion Resistance

Corrosive Agent	Concentration (%)	Temperature (°C)	Resistance Rating	Notes
Chlorides	3-5	25-60	Fair	Risk of pitting corrosion
Sulfuric Acid	10-20	25-50	Poor	Not recommended
Atmospheric	-	-	Good	Moderate resistance

GM190 exhibits moderate corrosion resistance, particularly in atmospheric conditions. However, it is susceptible to pitting corrosion in chloride environments and should be avoided in acidic conditions. Compared to stainless steels, GM190's corrosion resistance is limited, making it less suitable for marine or highly corrosive environments.

Heat Resistance

Property/Limit	Temperature (°C)	Temperature (°F)	Remarks
Max Continuous Service Temp	400 °C	752 °F	Suitable for moderate temperatures
Max Intermittent Service Temp	500 °C	932 °F	Short-term exposure only
Scaling Temperature	600 °C	1112 °F	Risk of oxidation beyond this limit

At elevated temperatures, GM190 maintains its strength but may experience oxidation. Care should be taken to avoid prolonged exposure to temperatures above 400 °C to prevent degradation of mechanical properties.

Fabrication Properties

Weldability

Welding Process	Recommended Filler Metal (AWS Classification)	Typical Shielding Gas/Flux	Notes
MIG	ER70S-6	Argon/CO2	Good for thin sections
TIG	ER70S-2	Argon	Excellent for precision
Stick	E7018	-	Requires preheat

GM190 is generally considered to have good weldability. Preheating may be necessary to avoid cracking, especially in thicker sections. Post-weld heat treatment can enhance the mechanical properties of the weld.

Machinability

Machining Parameter	GM190	AISI 1212	Notes/Tips
Relative Machinability Index	60%	100%	Moderate machinability
Typical Cutting Speed (Turning)	30 m/min	50 m/min	Use carbide tools for best results

GM190 has moderate machinability, which can be improved with proper tooling and cutting conditions. It is advisable to use high-speed steel or carbide tools for machining operations.

Formability

GM190 can be formed using both cold and hot processes. Cold forming is feasible but may lead to work hardening, which can affect ductility. Hot forming is preferred for complex shapes to avoid cracking and improve formability.

Heat Treatment

Treatment Process	Temperature Range (°C/°F)	Typical Soaking Time	Cooling Method	Primary Purpose / Expected Result
Annealing	600 - 700 °C / 1112 - 1292 °F	1 - 2 hours	Air	Reduce hardness, improve ductility
Quenching	850 - 900 °C / 1562 - 1652 °F	30 minutes	Oil/Water	Increase hardness
Tempering	400 - 600 °C / 752 - 1112 °F	1 hour	Air	Reduce brittleness, increase toughness

Heat treatment processes significantly affect the microstructure of GM190, enhancing its mechanical properties. Quenching increases hardness, while tempering reduces brittleness, making it suitable for various applications.

Typical Applications and End Uses

Industry/Sector	Specific Application Example	Key Steel Properties Utilized in this Application	Reason for Selection
Automotive	Engine Blocks	High strength, good machinability	Load-bearing capacity
Machinery	Gearboxes	Wear resistance, toughness	Durability under stress
Construction	Structural Components	Strength, weldability	Ease of fabrication

Other applications include:

• Pipelines
• Heavy machinery parts
• Railway components

GM190 is chosen for these applications due to its balance of strength, ductility, and ease of fabrication, making it ideal for components that require high performance under mechanical stress.

Important Considerations, Selection Criteria, and Further Insights

Feature/Property	GM190	AISI 4140	AISI 1045	Brief Pro/Con or Trade-off Note
Key Mechanical Property	Moderate	High	Moderate	GM190 is less strong than 4140 but easier to weld.
Key Corrosion Aspect	Fair	Good	Fair	GM190 is less resistant to corrosion than 4140.
Weldability	Good	Fair	Good	GM190 is easier to weld than 4140.
Machinability	Moderate	Good	Good	GM190 is less machinable than 1045.
Formability	Good	Moderate	Good	GM190 can be formed easily compared to 4140.
Approx. Relative Cost	Moderate	Higher	Lower	GM190 is cost-effective for many applications.
Typical Availability	Common	Less common	Common	GM190 is widely available in the market.

When selecting GM190, consider factors such as cost-effectiveness, availability, and the specific mechanical properties required for the application. While it may not offer the same strength as some alloy steels, its weldability and machinability make it a preferred choice for many engineering applications. Additionally, its moderate corrosion resistance makes it suitable for environments where exposure to corrosive agents is limited.

In summary, GM190 Cast Steel is a versatile material that balances strength, ductility, and ease of fabrication, making it a valuable choice in various industrial applications.