The Differences between Gray Cast Iron, White Cast Iron, Mottled Cast Iron and Ductile Cast Iron

The Differences between Gray Cast Iron, White Cast Iron, Mottled Cast Iron and Ductile Cast Iron

Classification of cast iron

According to the form of carbon, the cast iron covers three categories: gray cast iron, white cast iron and mottled cast iron.

  • Gray Cast Iron

Most of the carbon in gray cast iron is in the form of graphite. It is called gray cast iron, because its fracture is gray. Gray cast iron is the most common type, and which features a graphite microstructure consisting of many small fractures.

  •  White Cast Iron

While not as common as gray cast iron, white cast iron is another type worth mentioning. The carbon in white cast iron is completely in the form of cementite, and the fracture is bright white. White cast iron is difficult to machine so that it is mainly used as raw material for steelmaking. 

  • Mottled Cast Iron

The carbon in mottled cast iron exists in the form of a mixture of graphite and cementite, and the fracture is grayish-white. This cast iron has greater brittleness, so it is rarely used in industry.

 

According to the graphite form of cast iron, gray cast iron includes ordinary gray cast iron, vermicular cast iron, malleable cast iron and ductile cast iron.

Properties of cast iron 

  • Gray cast iron

The structure of gray cast iron is composed of graphite and matrix. In addition, the main factors affecting the structure and performance of gray cast iron are chemical composition and cooling rate.

  • Ductile cast iron

In actual engineering, with good casting performance, high tensile strength and high fatigue strength, ductile cast iron can replace steel to manufacture some important parts, such as crankshafts, connecting rods and camshafts.

Yide casting is a professional iron foundry in China, with 2 casting automatic casting production lines, and a manual sand castle working, we also equip the cat iron machining equipment in our machining workshop, if you are looking for good casting foundry, YIDE Casting is a good choice, please feel free to contact us for more details.

AISI 1040 SAE UNS G10400 Carbon Steel Foundry

AISI 1040 SAE UNS G10400 Carbon Steel Foundry

China’s steel foundry produces AISI 1040 SAE UNS G10400 carbon steel castings. The following is the material’s chemical composition, physical and mechanical properties and equivalent material grades.

Chemical Composition

ElementContent (%)
Iron, Fe98.6-99
Manganese, Mn0.60-0.90
Carbon, C0.370-0.440
Sulfur, S≤ 0.050
Phosphorous, P≤ 0.040

Physical Properties

PropertiesMetricImperial
Density (chemical composition of 0.435% C, 0.69% Mn, 0.20% Si, annealed at 860°C (1580°F))7.845 g/cc0.2834 lb/in³
Melting point1521°C2770°C

Mechanical Properties

PropertiesMetricImperial
Tensile strength620 MPa89900 psi
Yield strength415 MPa60200 psi
Bulk modulus (typical for steels)140 GPa20300 ksi
Shear modulus (typical for steels)80 GPa11600 ksi
Elastic modulus190-210 GPa27557-30458 ksi
Poisson’s ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)25%25%
Reduction of area50%50%
Hardness, Brinell201201
Hardness, Knoop (converted from Brinell hardness)223223
Hardness, Rockwell B (converted from Brinell hardness)9393
Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only)1313
Hardness, Vickers (converted from Brinell hardness)211211
Izod impact (annealed at 790°C (1450°F))45 J33.2 ft-lb
Izod impact (as rolled)49 J36.1 ft-lb
Izod impact (normalized at 900°C (1650°F)65 J47.9 ft-lb

Thermal Properties

PropertiesMetricImperial
Thermal expansion co-efficient (@ 20-100°C/68-212°F, composition of 0.40% C, 0.11% Mn, 0.01% P, 0.03% S, 0.03% Si, 0.03% Cu)11.3 µm/m°C6.28 µin/in°F
Thermal conductivity (@ 100°C/212°F)50.7 W/mK352 BTU in/hr.ft².°F
Thermal conductivity (@ 0°C)51.9 W/mK360 BTU in/hr.ft².°F

Other Designations

Other designations that are equivalent to AISI 1040 carbon steel include: ASTM A29 (1040), ASTM A510 (1040), ASTM A513, ASTM A519 (1040), ASTM A546 (1040), ASTM A576 (1040), ASTM A682 (1040), ASTM A827, ASTM A830, MIL S-11310 (CS 1040), MIL S-16788, MIL S-46070, SAE J1397 (1040), SAE J403 (1040), SAE J412 (1040)

Fabrication and Heat Treatment

  • Machinability

The cutting performance grade of AISI 1040 carbon steel is 60.

  • Forming

AISI 1040 carbon steel can be formed under annealing conditions.

  • Welding

AISI 1040 carbon steel can be welded using all welding techniques. Due to its high carbon content, it can be preheated at a temperature of 149 to 260°C (300 to 500°F) and heated at a temperature of 594 to 649°C (1100 to 1200°F).

  • Heat treatment

AISI 1040 carbon steel can be heat treated at 844 to 899°C (1550 to 1650°F), then quenched and tempered in water.

  • Forging

AISI 1040 carbon steel can be forged at a temperature of 982 to 1260°C (1800 to 2300°F).

  • Thermal processing

AISI 1040 carbon steel can be hot processed at a temperature of 94 to 483°C (200 to 900°F).

  • Cold working

AISI 1040 carbon steel can be cold worked in an annealed state using conventional methods.

  • Annealing

AISI 1040 carbon steel can be annealed at a temperature of 872 to 983°C (1600 to 1800°F). It can then be slowly cooled in the furnace. The stress relief annealing process can be performed at a temperature of approximately 594°C (1100°F). Normalized treatment can also be performed at 899°C (1650°F) and then slowly cooled.

  • Tempering

AISI 1040 carbon steel can be tempered at a temperature of 316 to 705°C (600 to 1300°F) depending on the required strength.

  • Hardening

AISI 1040 carbon steel can be hardened by cold work.

Applications of carbon steel casting

AISI 1040 carbon steel can be used for couplings, crankshafts and cold head parts.

Yide Casting is known as a professional steel foundry in China, has rich casting experience in casting and machining, we are committed to producing quality but competitive price casting steel parts for our customers, all of our casting parts have been marked as “JM”, we want to develop Yide casting, JM casting into the world, if you are looking for a steel foundry, please don’t hesitate to contact us, send us your drawing file, we’d like to serve you and provide best casting iron products.

AISI 1008 SAE UNS G10080 Carbon Steel

AISI 1008 SAE UNS G10080 Carbon Steel

Yide Casting in China produces AISI 1008 SAE UNS G10080 carbon steel castings. Today we will introduce to you the chemical composition, physical and mechanical properties and equivalent material grades of the material.

AISI 1008 carbon steel has excellent weldability, including protrusion, butt, spot welding and melting, and brazing. The following data sheets will provide more detailed information about AISI 1008 carbon steel.

Chemical Composition

ElementContent (%)
Iron, Fe99.31-99.7 %
Manganese, Mn0.30-0.50 %
Carbon, C0.10 %
Sulfur, S0.050 %
Phosphorous, P0.040 %

Physical Properties

PropertiesMetricImperial
Density (composition 0.06% C, 0.38% Mn, 0.01% Si, annealed at 925°C)7.872 g/cm30.2844 lb/in³

Mechanical Properties

PropertiesMetricImperial
Tensile strength340 MPa49300 psi
Yield strength (depending on temper)285 MPa41300 psi
Elastic modulus190-210 Gpa27557-30458 ksi
Bulk modulus (typical for steel)200 GPa29000 ksi
Shear modulus (typical for steel)80.0 GPa11600 ksi
Poisson’s ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)20%20%
Reduction of area45%45%
Brinell, Hardness,9595
Knoop (converted from Brinell hardness), Hardness113113
Rockwell B (converted from Brinell hardness), Hardness5555
Vickers (converted from Brinell hardness), Hardness9898
Machinability (based on AISI 1212 steel as 100 machinability) The machinability of group I bar, rod, and wire products can be improved by cold drawing)5555

Thermal Properties

PropertiesMetricImperial
Thermal expansion co-efficient (@0.000-100°C/32-212°F)12.6 µm/m°C7 µin/in°F
Thermal conductivity (composition of 0.06% C, 0.4% Mn; 0°C )65.2 W/mK452 BTU in/hr.ft².°F

Equivalent Materials

AMS 5040F, AMS 5042F, AMS 5044D, AMS 5047Ac, AMS 5050F, AMS 5053C, ASTM A108, ASTM A29, ASTM A510, ASTM A519, ASTM A545, ASTM A549, ASTM A575, ASTM A576, SAE J403, FED QQ-S-698 (C1008), MIL-S-11310 (CS1008), FED QQ-S-637 (C1008), UNI CB 10 FU, SAE J1397, SAE J412, SAE J414, ASTM A512, ASTM A513, ASTM A575, ASTM A576, ASTM A635, ASTM A830, DIN 1.0204.

Applications

AISI 1008 carbon steel is primarily used in extruded, cold-headed, cold upset, and cold-pressed parts and forms.

Yide casting can provide iron casting and machining services, as an experienced iron casting foundry in China. We also cooperate with cast steel factories, so as to broaden our range of service. If you have any requirements or questions about cast iron, please don’t hesitate to contact us for more details.

How to Clean Gas Stove Burner Holes

How to Clean Gas Stove Burner Holes

Gas burners are also called stove burners or gas stove burners, produced by brass casting or iron casting. As a leading iron foundry in China, Yide casting has rich experience in iron casting, we provide quality brass cast gas stove burner and iron cast gas stove burner, producing gas burners in China for many years. Therefore, we have always wanted to write an article for buyers to understand all the issues related to gas burners.

Applications

The gas burner is a gas combustion device, which makes gas and air enter the combustion zone separately or mixed to achieve stable combustion. Fuel gas includes acetylene, natural gas or propane. Gas burners are widely used in residential and industrial fields, from ordinary kitchen stoves to hospitals, restaurants, outdoor grills, industrial stoves and boilers.

Types

There are hundreds of types of gas burners. We only list some of them, such as portable stoves, outdoor gas stoves, natural gas stoves, propane gas stoves, burners, large stoves, small stoves, star stoves, single stoves, rectangular stoves, frying boilers, camping gas stoves, double Gas stove, fireplace gas stove, portable gas stove, LP gas stove, commercial gas stove, butane gas stove, etc.

Materials

According to our experience, most gas burners will use gray cast iron ASTM A48 Class20 or Class30, but Class35 is rarely used. Why, because small fire-proof holes need to be processed, so if the hardness of the material is too high, it will be difficult to drill. You can’t compare these holes with other ordinary holes, and it will be more difficult to drill holes in small buttons. Moreover, the strength of class20 should be sufficient for the application.

If you want to learn more about the degree of these materials through other standards (such as Germany, Japan, United Kingdom, or ISO), please check the material comparison of gray cast iron here.

1.ASTM A48 grade 20 is equal to GG15, HT150, FC150, ISO150.
2. ASTM A48 Class 30 is equal to GG20, HT200, FC200, ISO200.
3. ASTM A48 Class 35 is equal to GG25, HT250, FC250, ISO250.

Some buyers may choose a higher degree to obtain stronger parts, and we do not recommend that you do this. The higher the degree, the more difficult the production, the higher the defective rate, and the higher the cost. As for the gas burner, too high tensile strength is not required.

Casting Process

Based on our experience, we recommend using two casting processes to produce gas burners. One is green sand as the outer shell and resin sand as the core. We make the core through the shell molding process, which means that we first make a pre-coated resin sand core, and then use ordinary floor molding with green sand to produce the shell. By the way, the inner surface is good and the outer surface is normal. This process can meet your requirements with the lowest production cost. Of course, green sand must be very fine, ordinary coarse sand is not acceptable.

The other process is to manufacture the shell and core through the pre-coated resin sand and shell molding process. By the way, the inner and outer surfaces are good, but the production cost is higher. Therefore, the buyer should choose the appropriate casting process according to the specific application.

Processing

The only problem with gas burner processing is the processing of exhaust holes. Sometimes, there are dozens to hundreds of fire-proof holes on the gas burner. They need to drill. If you fail to drill one of them, the gas burner will malfunction, so it is not easy to drill according to your ideas. The Dandong Foundry used several small drilling machines for drilling. Several workers are responsible for drilling these small holes every day.

Mode

As for the mold of the gas burner. According to our experience, we recommend using iron molds to make resin cores and aluminum molds to make gas burner shells. However, in order to obtain a better external surface quality, resin sand should be considered for the shell, and then iron patterns must be used as the shell. All in all, the gas burner must have a metal pattern.

Surface Coating

There are several types of surface coatings for gas burners. One is black heat-resistant paint, the other is normal black paint, which is cheaper than a heat-resistant air cushion, and the third paint uses anti-rust oil. Heat-resistant coatings are the most expensive coatings, from about US$0.23 to US$0.25/kg. If your gas burner weighs 1kg, the price of its heat-resistant paint is about 0.23 to 0.25 USD/pcs.

Supplier

Although many iron foundries can produce gas burners, not everyone can produce gas burners at a low price, and the production efficiency is high. This is mainly because they should use fine sand and should have experience in drilling many small holes. Most importantly, extreme care should be taken during casting, cleaning and machining. Any hasty operation will lead to malfunction. Therefore, it is difficult to find a good gas burner supplier.

Price

The price of a gas burner is mainly related to the unit weight (especially the weight of the blank casting), the number of exhaust holes, the complexity of the structure and the surface quality of the outer surface.

Defects

The main defects of gas stove heads are blisters on the surface (baths with a diameter of 2mm and a depth of 1mm are usually allowed), damage to the vent holes, and dirty surfaces with sand. Please note that welding is not allowed under normal circumstances, because the stove burner should be airtight.

 

Yide casting is a professional casting manufacturer, focuses on manufacturing top quality ductile cast iron, grey cast iron, cast steel, brass casting, bronze casting for our customers since 1993. In addition, Yide casting also keeps a top passion for advanced technology in the gas stove burners casting. If you are looking for a stove burner foundry, please don’t hesitate to contact us,

DIN ISO 1302, DIN 4768 – Comparison of Surface Roughness Values

DIN ISO 1302, DIN 4768 – Comparison of Surface Roughness Values

DIN ISO 1302 and DIN 4768 are German standards for surface roughness in various fields (including metal castings). The following table is the explanation of the symbols and comparison with the surface roughness values.

Surface Roughness Symbols

Explanation

Symbol without additional indications.
Basic symbol. The meaning must be explained by additional indications.
Symbol with additional indications.
Any production method, with specified roughness.

Symbol without additional indications.
Removal of material by machining, without specified roughness.

Symbol with additional indications.
Removal of material by machining, with specified roughness.

Symbol without additional indications.
Removal of material is not permitted (surface remains in state as supplied).

Symbol with additional indications.
Made without removal of material (non-cutting), with specified roughness.

Comparison of Roughness Values

DIN ISO 1302Roughness Values Ra (um)0.0250.050.10.20.40.81.63.26.312.52550
Roughness Values Ra (uin)124816326312525050010002000
Roughness Grade NumbersN1N2N3N4N5N6N7N8N9N10N11N12
DIN 4768Roughness Values Rz (um) from0.10.250.40.81.63.156.312.5254080160
to0.81.62.54.06.312.52031.563100160250

For more information, please refer to Surface Finish Degree (Smoothness) Comparison Table between Rz, Ra and RMS.

 

Yide casting has our own casting factory and machining workshop, we always accept drawing file and parameters from our casting iron customers, and then make an iron cast sample according to the whole requirements, ship it to you, arrange production or casting again after you check the cast iron sample. We will refund the sample cost after big production, if you are looking for a casting iron foundry, please don’t hesitate to contact us for more details.

The Differences Between Casting and Forging

The Differences Between Casting and Forging

1. Different production process:

Casting is a processing method in which the metal is melted into a liquid and poured into a mold, and then cooled, solidified and cleaned to obtain a casting of the desired shape. Casting can produce various objects with complex shapes.

Forging is to use methods such as hammering to make a metal material in a plastic state into a workpiece with a certain shape and size, and to change its physical properties.

2. Forging and casting purposes:

Casting is a relatively economical method of forming blanks, which is generally used for parts with complex shapes.

Forging is generally used in the processing of forgings of a certain shape and size.

3. Advantages of casting and forging:

Casting:

  1. It can produce parts with complex shapes, especially blanks with complex cavities.
  2. Wide adaptability in size, from a few grams to hundreds of tons.
  3. Wide sources of raw materials, low prices, such as scrap steel, scrap parts, chips, etc.
  4. The shape and size of the casting are very close to that of the parts, which reduces the amount of cutting, which is non-cutting.
  5. Widely used. 40% to 70% of agricultural machinery and 70% to 80% of the weight of machine tools are castings.

Forging:

Forging can eliminate defects such as loose as-cast during the smelting process and optimize the microstructure. At the same time, due to the preservation of the complete metal streamline, the mechanical properties of forgings are generally better than castings of the same material.

4. Disadvantages of casting and forging:

Casting:

  1. The mechanical properties are not as good as forgings, such as coarse structure and many defects.
  2. In sand casting, single piece and small batch production, the labor intensity of workers is high.
  3. The quality of castings is unstable, there are many procedures with the complicated influencing factors.

Forging:

  1. In forging production, trauma accidents are prone to occur.
  2. The cost is much higher than casting.

Yide Casting is known as a professional iron foundry in China, has rich casting experience in casting and machining, we are committed to producing quality but competitive price casting iron parts for our customers, all of our casting iron parts has been marked as “JM”, we want to develop Yide casting, JM casting into the world, if you are looking for a casting iron foundry, please don’t hesitate to contact us, send us your drawing file, we’d like to serve you and provide best casting iron products.

AISI 1020 Carbon Steel 

AISI 1020 Carbon Steel

AISI 1020 Carbon Steel is a high grade steel material. Today, we will introduce the chemical composition, physical and mechanical properties and equivalent material grades of this grade material for you.

Chemical Composition

ElementContent (%)
Manganese, Mn0.30-0.60
Carbon, C0.18-0.23
Sulfur, S0.05 (max)
Phosphorous, P0.04 (max)
Iron, FeBalance

Physical Properties

PropertiesMetricImperial
Density7.87 g/cm30.284 lb/in3

Mechanical Properties

PropertiesMetricImperial
Tensile strength420 MPa60900 psi
Yield strength350 MPa50800 psi
Modulus of elasticity205 GPa29700 ksi
Shear modulus (typical for steel)80 GPa11600 ksi
Poisson’s ratio0.290.29
Elongation at break (in 50 mm)15%15%
Hardness, Brinell121121
Hardness, Knoop (converted from Brinell hardness)140140
Hardness, Rockwell B (converted from Brinell hardness)6868
Hardness, Vickers (converted from Brinell hardness)126126
Machinability (based on AISI 1212 steel. as 100 machinability)6565

Fabrication and Heat Treatment

  • Compared with AISI 1112 carbon steel, AISI 1020 carbon steel has good workability, reaching 65%.
  • Thanks to the high ductility, it is easy to form AISI 1020 carbon steel using all conventional methods.
  • It is easy to weld this alloy by using all traditional methods.
  • This Alloy can be hardened by heating at 815-871°C (1500-1600°F), then water quenching and temperature adjustment.
  • AISI 1020 carbon steel should be forged at a temperature of 1260°C (2300°F) to 982°C (1800°F).
  • AISI 1020 carbon steel can be hot processed in the temperature range of 482 to 649°C (900 to 1200°F).
  • All conventional methods can be used to cold work AISI 1020 carbon steel. If cold working is performed for a long time, stress relief annealing is recommended.
  • The alloy can be fully annealed between 871-982°C (1600 to 1800°F), and then slowly cooled in the furnace. This will provide the alloy with a tensile strength of approximately 65 ksi. If required, stress relief annealing can be performed at 538°C (1000°F).
  • After tempering, it should be heat treated and quenched at a temperature of 315 to 538°C (600 to 1000°F) according to the required strength level. For example, tempering at 538°C (1000°F) can provide the alloy with a tensile strength of 90 ksi.
  • AISI 1020 carbon steel can be hardened by cold working and heat treatment, quenching and tempering.

Applications

AISI 1020 carbon steel is used for simple structural applications, such as cold bolts. Usually used when the surface is hardened.

At the same time, it is also suitable for producing pins, shafts, chains, lightly stressed gears, hard wearing surfaces, and case hardened components where core strength is not essential.

 

steel caster wheels from JM casting factory

Yide casting is an experienced iron casting foundry, provides iron casting service and machining service, we also have a cast steel casting factory to cooperate, if you have any casting requirements, please don’t hesitate to contact us for more details.

Machining Surface Finish Chart, Comparator, Method, Degree, Ra, Rz, RMS

Machining Surface Finish Chart, Comparator, Method, Degree, Ra, Rz, RMS

The surface finishes smooth degree is an important requirement, as for the machining to steel and iron castings.

Today, Yide Casting will introduce the conversion in China and USA standard for Ra (um), Ra (micro inch), Rz (um), RMS and finish degree, and the related finish methods as well.

China
Finish Degree
China
Ra (um)
China
Rz (um)
USA
Ra (um)
USA Ra
(micro inch)
USA RMS
(micro inch)
Machining Finish Method
refer to iron-foundry.com
15020050.020002200The most coarse machining or good rough casting surfaces
22510025.010001100Machining marks very obvious.
Rough turning, boring, planning, drilling.
312.55012.5500550Machining marks obvious.
Rough turning, planning, milling, drilling.
46.3258.00320352Machining marks visible.
Normal turning, boring, planning, drilling, grinding.
6.30250275
53.212.55.00200220Machining marks not obvious, but still visible.
Normal turning, boring, planning, drilling, grinding.
4.00160176
3.20125137.5
61.66.32.50100110Machining marks blur, but marks direction obvious.
Number controlled turning, boring, planning, drilling, grinding.
2.008088
1.606369.3
70.86.31.255055Machining marks direction blur, but still visible.
Number controlled turning, boring, planning, drilling, grinding.
1.004044
0.803235.2
80.43.20.632527.5Machining marks direction blur.
Reaming, grinding, boring, rolling.
0.502022
0.401617.6
90.21.60.2012.513.75Machining marks direction invisible.
Grinding, super machining.
1011
88.8
100.10.80.1044.4Surface dark gloss.
Super machining.

The surface finish comparator for milling, turning, reaming and grinding

Yide Casting is a leading iron foundry, provide both casting service and machining service, equipped with imported advanced machining machines in our machining workshop, if you have both casting and machining demands, Yide casting is a good choice for you, we promise good quality casting and machining requirement,  please feel free to contact us for more details.

Brinell Hardness Test

Brinell Hardness Test

Test principle of Brinell hardness

The calculation formula of Brinell hardness is:

Among them, the unit of HB is kgf/
d——Indentation diameter, mm; h——Indentation depth, mm.
As long as the diameter of the indentation is measured, the HB value can be obtained by calculation or look-up table.

During the test, choose different loads and steel ball diameters according to the nature and shape of the material.

The advantages of the Brinell hardness test are strong representativeness, good data repeatability. At the same time, there is a certain conversion relationship with strength. The disadvantage is that harder materials cannot be tested; the indentation is large and not suitable for finished product inspection. It is usually used to test the hardness of raw materials and tempered parts, such as cast iron, non-ferrous metals, low alloy steel, etc.

 

Test conditions

In the Brinell hardness test, we should select the diameter (D) of the indenter sphere, the test load (F), and the load holding time (t), according to the type of metal material, the range of hardness values ​​and the thickness. There are five commonly used indenter diameters of 1, 2, 2.5, 5 and 10 mm.
The test load can range from 9.807N (1kgf) to 29.42 KN (3000 kgf).
The load holding time is generally 10-15s for ferrous metals; 30s for non-ferrous metals; 60s when the HB value is less than 35.

 

Pros and Cons

The diameter of the steel ball and the indentation left on the surface of the metal material is large. Therefore, the measured hardness value is more accurate. There is a certain relationship between HB value and tensile strength. That means we can determine the tensile strength of metal materials approximately according to the Brinell hardness value.
If the hardness of the metal is too high, it will affect the accuracy of the hardness value. Therefore, the HB test is generally suitable for measuring metal materials with a HB value of less than 650.
The Brinell hardness indentation is relatively large, so it is not suitable to measure finished products and sheet materials.

Yide casting is a leading casting foundry in China, we produce quality casting products, pursuing details required for every casting product, we have an imported testing machine to check the Brinell hardness and other parameters, committed to proving the best casting service for our casting customers.

ASTM A48 Standard for Gray Iron Castings

ASTM A48 Standard for Gray Iron Castings

ASTM A48 / A48M Standard Specification for Gray Iron Castings, grades including Class No. 20, 25, 30, 35, 40, 45, 50, 55, 60.

Class No. 20 A, 20 B, 20 C, 20 S,
Class No. 25 A, 25 B, 25 C, 25 S,
Class No. 30 A, 30 B, 30 C, 30 S,
Class No. 35 A, 35 B, 35 C, 35 S,
Class No. 40 A, 40 B, 40 C, 40 S,
Class No. 45 A, 45 B, 45 C, 45 S,
Class No. 50 A, 50 B, 50 C, 50 S,
Class No. 55 A, 55 B, 55 C, 55 S,
Class No. 60 A, 60 B, 60 C, 60 S.

This specification covers general engineering gray iron castings mainly used for tensile strength. The castings are classified according to the tensile strength of the cast iron in the individually cast test rods.

1. Requirements for Tensile Strength

On the above chart, you can see that each material grade requires its minimum value of tensile strength, ksi. That means the tensile strength is the most important specification for gray iron castings.

However, there is no need to write A, B, C, S material grades for the foundry. Because A, B, C, and S are only requirements for test bar.

For example, for a cast iron plant, ASTM A48 Class 20 will be sufficiently detailed, which means the minimum value. The tensile strength of gray cast iron must be higher than 20 ksi (138 Mpa).

ASTM A48 Class 20: Min. Tensile Strength 20 ksi (138 Mpa)
ASTM A48 Class 25: Min. Tensile Strength 25 ksi (172 Mpa)
ASTM A48 Class 30: Min. Tensile Strength 30 ksi (207 Mpa)
ASTM A48 Class 35: Min. Tensile Strength 35 ksi (241 Mpa)
ASTM A48 Class 40: Min. Tensile Strength 40 ksi (276 Mpa)
ASTM A48 Class 45: Min. Tensile Strength 45 ksi (310 Mpa)
ASTM A48 Class 50: Min. Tensile Strength 50 ksi (345 Mpa)
ASTM A48 Class 55: Min. Tensile Strength 55 ksi (379 Mpa)
ASTM A48 Class 60: Min. Tensile Strength 60 ksi (414 Mpa)

If you want to know the equivalent grades of other standards, please refer to the equivalent grades of gray iron and ductile iron.

2. Dimension Requirements

The castings should conform to the dimensions or drawings provided by the purchaser. If there is no drawing, it shall conform to the predicted size of the pattern equipment provided by the purchaser.

Usually, the buyer should provide 3D drawings and 2D drawings. 3D engineering drawings will make patterns more accurately. The 2D engineering drawing will provide detailed dimensional tolerances and processing requirements. Therefore, this will avoid confusion and misunderstanding, and drawings are the only standard for dimensions.

If the purchaser does not have a drawing, he should provide an original sample. Our Yide Casting can scan samples into 3D engineering drawings, so the size of the samples will become the standard. The problem is that the casting foundry should ask the buyer for the tolerance of the key dimensions, because the sample cannot show the tolerance range in the drawing.

3. Quality and Defects Requirements

There should be no visible sand, scale, cracks and thermal cracks on the surface of the casting.

Unless the purchaser’s written permission is obtained, repairs shall not be carried out by any form of splicing or welding.

Generally, the foundry should have enough experience to deal with defects. However, when there is a defect, the foundry should discuss with the purchaser to confirm whether leak plugging and welding can be carried out.

For metal castings, defects on the surface and internal areas are inevitable, so it is essential for the foundry to conduct good quality inspections and communicate with customers in a timely manner. If you want to know the appearance of casting defects, please refer to Yide Casting’s article: Photos of casting defects.

4. Cast Test Rods

The test rod should be an independent casting of the same batch as the representative casting, and have the dimensions shown in Table 4. You can leave a margin for a reasonable template draft within the tolerance range shown in Table 4. Test rods A, B and C are all standard test rods in the form of simple cylinders. The test rod S is special and is intended to be used where the standard rod is not satisfactory.


5. Special Requirements

If a written agreement is reached between the manufacturer and the purchaser, the casting may have to meet special requirements regarding hardness, chemical composition, microstructure, pressure tightness, radiographic robustness, size, surface finish, etc.

This means that buyers may ask for more if necessary. ASTM A48 is only the standard for the main mechanical properties of gray cast iron. If the buyer has the above-mentioned special requirements, he should inform the manufacturer at the beginning.

6. Mechanical Properties of Gray Iron Castings

Grade 20, 25, 30 and 35 gray cast irons have excellent machinability, high damping capacity, low modulus of elasticity and relatively easy manufacturing.

Grade 40, 45, 50, 55, and 60 gray cast irons are generally more difficult to machine, have lower damping capacity, higher modulus of elasticity, and are more difficult to manufacture.

Higher grade means higher tensile strength, higher hardness, higher price and difficulty of production, so you must know which material grade is suitable or sufficient for your project without having to pursue the highest grade.

Yide casting is a leading casting foundry in China, specialized in iron casting and machining, can meet kinds of requirements of your casting products, if you are looking for experienced iron foundry, please feel free to contact us for more details.