ASTM A48 Class 20 (Related Standards – ISO 185/JL/150, SAE J431, EN-GJL-150) is a
Grade 20 cast iron is grey cast iron in the as-fabricated (no temper or treatment) condition. Grade 20 is the ASTM designation for this material. 150 is the ISO numeric designation.
V-2 (class 40) Gray Iron, ASTM B48:
V-2 is ideally suited for straight wear applications and possesses the highest strength, hardness, resistance to wear and heat treat response for an unalloyed gray iron.
ASTM A48 class 25 is a material grade of gray cast iron in USA, which is higher than class 20, but lower than class 30. Its UNS number is F11701. There are four specific grades as ASTM A48 class 25A, 25B, 25C and 25S.
ASTM A48 class 30 is the most common material of gray cast iron. It is USA grade, also equal to GG20 in Germany, HT200 in China, FC200 in Japan, G20 in Italy, T220 in Australia or ISO 200. According to the standard of ASTM A48, this material has min. tensile strength 207 Mpa.
Spheroidal graphite cast iron 420/12 (BS EN 1563:1997), also known as ductile cast iron, is a type of cast iron that has been treated while molten with an element such as magnesium or cerium to induce the formation of free graphite as nodules or spherulites.
White Cast Iron
The absence of graphite in its structure contributes to its characteristic hardness, making it one of the toughest members in the cast iron family. The crystalline structure of white cast iron renders it exceptionally hard and brittle, with a high level of resistance to wear and abrasion.
The value of antique cast iron skillets can start at similar to new prices, but a super rare Wagner or Griswold can fetch up to $1,500 apiece. A mint condition, super rare "spider skillet" made in the 1890s by Griswold is worth up to $8,000.
Oftentimes, the letters and numbers you'll find on the bottom of a vintage pan denote a pattern number or correspond to a particular cooking surface on a stove the pan might've been sold with, and unusual notches could be a maker's mark incorporated into the piece to identify the actual person who crafted it.
Final Verdict. If you're looking for cast iron that ranked highly across the board, check out the triple-seasoned Lodge Cast Iron Blacklock Skillet. For a budget option, we recommend the Lodge Cast Iron Skillet, which performed well and is lightweight, making it incredibly user-friendly.
Magnetite is the finest iron ore with a very high content of iron up to 70 per cent. It has excellent magnetic qualities, especially valuable in the electrical industry. Hematite ore is the most important industrial iron ore in terms of the quantity used, but has a slightly lower iron content than magnetite.
Gray Cast Iron Disadvantages
The biggest disadvantage of gray cast iron is its low tensile strength. This results from the graphite flakes within the material – which also give it many of its benefits.
foundry pig iron (also known as haematite pig iron): used in mainly in the manufacture of grey iron castings in cupola furnaces.
Class 40 Gray Iron is a ferrous foundry metal that has been alloyed with carbon and silicon. Carbon is added to the base melt in amounts that exceed the solubility limits in iron and precipitates out as graphite particles.
Grey cast iron is characterised by its graphitic microstructure, which causes fractures of the material to have a grey appearance. It is the most commonly used cast iron and the most widely used cast material based on weight.
Griswold Cast iron Is Highly Collectible.
And this makes the ironware fun to collect for collectors and enthusiasts. So when a rare piece or size comes up for sale, it will attract the attention of many buyers and ultimately drive up the price.
The most sought after Wapak cast iron are the pans with the “Indian head" medallion on them, which was produced from 1903-1926. The rarest and most collectible is the #4 skillet--until recently.
All categories of cast iron except white iron are considered as weldable, although the welding can be significantly more difficult compared with carbon steel welding. However, it can be difficult to tell the difference between these different types of cast iron without detailed metallurgical analysis.
On the other hand, stainless steel is a great choice for durability and even heat distribution and is one of our favorite skillet materials. Carbon steel is another excellent choice for these properties and is a lightweight alternative to cast iron. Like cast iron, though, it will need to be seasoned and maintained.
This black residue from your cast-iron pan doesn't look great, but it's just seasoning and it's not harmful. Keep cooking in that pan, washing and drying and oiling it meticulously, and you'll see the issue clear up quickly.
High duty cast irons are inoculated with calcium silicide. It is essentially a gray iron containing free graphite which is graphitised in a controlled manner in the ladle.
Grade A: Grade A black steel pipe typically has a maximum carbon content of 0.25% and a manganese content ranging from 0.95% to 1.44%. These pipes are designed for general structural and mechanical applications and are typically specified for low pressure fluid transfer and non-critical industrial uses.