Iron Castings Specifications
All our castings are produced to a current ISO specification, ISO 185 2005, along with any further certification which a customer may require. Our diverse customer base has given us experience in a wide range of applications for iron castings across many market sectors including pumps and valves, forges, foundries and rolling mills, automotive and aerospace, a wide range of OEMs, quarries and mines, railways and rolling stock, local authorities and artists and sculptors.
We also have long term trading relationships with local pattern makers, machine shops and surface finishers which enable us to quote for the complete supply of machined and painted castings.
Iron Castings Quantities
Iron castings of the size and quantity that Durham Foundry produces are traditionally made in sand moulds. The earliest type of sand system was Greensand, which is a combination of silica sand, clay and water, a naturally occurring sand which contains clay being used as the basis for the system.
This sand is usually red in colour, although after use in a foundry the sand takes on a dark grey/brown colour. This can cause confusion when foundrymen talk about “green” sand. The term green is used to denote that the sand is wet, having about 2% water in it. If greensand is compacted around a pattern, the sand will retain its shape after the pattern is removed, which occurs because the clay in the sand provides an electrostatic bond between the clay and the sand grains.
The more the sand is worked or rammed the greater the electrostatic charge that builds up and the stronger the final mould will be.
One area of potential confusion is the spelling of the word ‘grey’. This can be spelt either as ‘grey’ or as ‘gray’ although gray tends to be an American usage.