James Durrans Refractory Coatings, Recarburisers, Sand Additives and Graphite

Selection and quotation of James Durrans foundry materials: RWB, RSB, FM and Diecote coatings, PREMCO and PROCARB recarburisers, sand additives and natural graphite.

RWB, RSB, FM and Diecote Refractory Coatings

Durrans refractory coatings are suspensions of fine refractory fillers in water or isopropyl alcohol. They prevent metal-mould reactions such as penetration, veining and erosion and improve the surface finish. Each alcohol based RSB coating has a water based RWB counterpart.

Water based RWB series, e.g. zircon RWB 1001 for steel and heavy iron
Alcohol based RSB series in 99.9% IPA
FM series for full-mould work with colour change on drying
Diecote series for die and centrifugal moulds

Carboform Carbon Blackings for Furnace Refractories

Durrans carbon based blackings are brushed or sprayed onto hot furnace linings, troughs and pouring lips. They harden into a stable, abrasion resistant layer that protects the refractory from attack by molten metal and from metal adhesions.

Applied to a hot surface by brushing or spraying
Carboform and Carboform ZD paste stands 24 hours before use
Protects troughs and pouring lips against melt adhesions
No.15 Chillroll blacking for rolls in metallic moulds

PREMCO, PROCARB and CARBON 99 Recarburisers

Durrans recarburisers adjust the carbon content of liquid iron and steel. The range is graded by sulphur: low sulphur PREMCO and PROCARB synthetic graphites and CARBON 99 grades with higher sulphur. Packing options include 25 kg bags and 1,000 kg big bags.

PREMCO EG: 99.0% C, 0.04% S
PROCARB SG: 98.5% C, 0.05% S
CARBON 99 GPR40: 98.5% C, 1.50% S
Packing: 25 kg bags and 1,000 kg big bags

Green Sand and Core Sand Additives

For green sand systems Durrans makes graded coal dust and Pulverbond bentonite blends with coal. They create a reducing atmosphere in the mould and prevent metal penetrating into the sand. Coarse grained carbons for cold box cores alleviate the effects of veining.

Pulverbond G bentonite: 85% montmorillonite
Typical coal and bentonite blend 50:50
Coarse coal grades for vertical Disa moulding
Core sand carbons for cold box cores against veining

Natural Flake, Amorphous and Expandable Graphite

Durrans dries, grinds, blends and grades natural graphite at its Penistone plant in South Yorkshire. Flake graphite comes in fine, medium and coarse grades, amorphous and powdered graphite as fine powders. Expandable graphite grows up to 300 times in volume when heated.

Flake graphite with 80 to 98% carbon
Powdered graphite: 80% passing 200 mesh (75 microns)
Expandable graphite: 80 to 300 times volume increase
Low ash grades and blending to customer specification

Durcol Graphite Lubricants for Hot Forging

For over 20 years Durrans has made lubricants for the forging industry: water and oil based graphite lubricants, synthetic lubricants and release agents. A good lubricant reduces friction, eases removal of the forged part from the die and extends die life.

Durcol W1020-01: micronised graphite in water
Durcol 1020C-RO-03: colloidal graphite in vegetable oil
Water and oil based graphite lubricants for forging
Synthetic lubricants and release agents

Choosing a Refractory Coating by Alloy

The alloy and pouring temperature set the main refractory filler. Zircon RWB 1001 or high wear resistance alumina RWB 6003 suit steel and heavy iron, magnesia RSB 4401 suits manganese steel, and carbon RSB 5302 suits non-ferrous alloys, grey iron and ductile iron.

Phyllosilicate coatings such as RWB 3321 counteract veining on automotive cores. For 3D-printed cores or moulds Durrans offers RSB 3321-3D and RWB 3321-3D.

Matching Recarburiser Sulphur to the Iron Grade

The choice of recarburiser depends on the iron alloy produced. Ductile iron (GJS), vermicular graphite iron (CGI) and special steel grades require low sulphur, while grey iron (GJL) normally needs only a medium sulphur grade.

The lower the sulphur, the higher the raw material cost: by the maker's own calculation PROCARB LS with up to 0.15% S gives better value than PREMCO SG with 0.05% S. At least one sample of molten iron should go for chemical analysis to confirm the carbon level.

Reading a Natural Graphite Grading Code

A plus or minus sign in a Durrans graphite code shows whether 80% of the material stays on or passes the sieve, and the last two digits give the carbon content. So -285 means 80% below 200 mesh (75 microns) with 85% carbon, and +192 means 80% above 100 mesh (150 microns) with 92% carbon.

Grading is available down to very fine grades of less than 5 microns.

Choosing a Coal Dust Grade for Green Sand

Graded coal is added to green sand together with bentonite to create a reducing atmosphere in the mould and prevent metal penetrating into the sand. Coarse grades serve high pressure vertical moulding lines such as Disa units, medium and finer grades serve horizontal plants.

A typical blend is 50:50 coal and bentonite, or 40:10:50 with lustrous carbon. Bentonite blends give safer handling and no ADR transport regulations for the coal.

James Durrans and model names are trademarks of their respective owners and are used only to identify the equipment for which we source parts. SpareX is not an official dealer, distributor or representative of James Durrans and is not affiliated with the trademark owner. Origin, documents and warranty are stated for each item in the quotation.