WO2003074640A1

WO2003074640A1 - Graphite-based forging lubricants

Info

Publication number: WO2003074640A1
Application number: PCT/US2003/006046
Authority: WO
Inventors: Robert J. Bourret; Peter L. Zaleski
Original assignee: Superior Graphite Co.
Priority date: 2002-03-01
Filing date: 2003-02-28
Publication date: 2003-09-12
Also published as: AU2003224636A1

Abstract

Two high temperature lubricants adapted to be applied by an airless spray system are disclosed. The first is designed for use at temperatures of between 200 to 315°C and comprises a combination of water, graphite, montmorillonite, xanthan gum, surfactant/defoamer and a preservative. The second is designed for use of temperatures between 425 and 540°C and includes any combination of water, silicate resin, surfactant/defoamer,

Description

GRAPHITE-BASED FORGING LUBRICANTS

BACKGROUND

[0001] The present invention relates to a graphite-based, high temperature forging lubricant suitable for application by means of an airless spray.

[0002] Forging shops currently use a swapping or air-assisted pump and delivery system to apply graphite-based lubricants to the die surfaces. When using an air-assisted delivery system, a number of problems arise. These include the lubricant being applied to the die to cool it to the desired temperature at which the lubricant will stick, resulting in the waste of lubricant during the cooling. Also, when the die goes through thermal cycling because of its cooling during the lubricant application, stresses are created in the die which reduce the die life.

[0003] Air-assisted delivery also uses pressure from the pump to accelerate the lubricant towards the die in order to assist sticking. Unfortunately, the graphite that does not stick to the die rebounds and becomes airborne and migrates through the facility, resulting in potential health problems and an undesirable work environment.

DETAILED DESCRIPTION

[0004] The present invention relates to graphite lubricants designed to work for specific die temperatures and applied by airless pumping/delivery systems. The pumping/delivery systems appropriate for application of these lubricants are commercially available from Coating Management Technology in Tornio, Finland, as the Pro-Hydro 500 Forge Shop liquid transfer and pumping system. The lubricant may be made according to the continuous process described in U.S. Patent No. 6,169,059, incorporated herein by reference, or by a batch process.

[0005] Two high-temperature graphite lubricants according to the present invention are exemplified in Tables IA, IB, IIA and IIB. Tables IA and IB show a lubricant for application to a die having a temperature between 400-600°F (200-315°C) . Tables IIA and IIB show a lubricant for application to a die having a temperature between 800-1, 000°F (425-540°C) . Example I is a specific formulation for a lubricant in accordance with Tables IA and IB, while Example II is a specific formulation of a lubricant in accordance with Tables IIA and IIB.

TABLE IA

TABLE IB

EXAMPLE 1

TABLE IIA

TABLE IIB

EXAMPLE 2

[0006] The graphite may be any material from the graphite chemical family, both natural and synthetic, preferably having an average particle size d50 of from 15-25μm and LOI of greater than 99.0%. In the Examples, synthetic graphite is used, specifically 5035 grade synthetic graphite available from the Superior Graphite Co. This is a high purity graphite that has a minimum of 99.0% carbon (LOI) (99.8% typical); a maximum of 1% ash (0.2% typical); a maximum of 0.5% moisture (0% typical); and a maximum of 1.5% volatiles (0.5% typical). The 5035 grade graphite is sized so that a minimum of 99% passes through a sieve of 325 U.S. mesh. However, the particle size may range between 4 to 75 microns .

[0007] The water may be tap water of a quality suitable for industrial applications, and without harmful impurities.

[0008] The preservative may be any material classified as a preservative, such as a biocide, which is suitable for metal working fluids, paints, coatings and/or suspensions. Its purpose is to protect the organic components of the suspension from micro-biological decomposition. The preservative may be, for example, a 50% solution of glutaraldehyde, such as Ucarcide 250 preservative available from Union Carbide or Ucar Carbon Company.

[0009] The dextrin may be any material from the dextrin chemical family, and is preferably greater than 90% soluble in water. With heat, dextrin cooks into a tacky adhesive and finally decomposes into carbon, gases and ash. Stadex 126 dextrin available from the Staley Co. has provided satisfactory results .

[00010] The xanthan gum may be any materials from the xanthan gum chemical family and preferably has an average particle size of 175 microns. Xanthan gum is a suspension agent and prevents the solid particles from settling. The xanthan gum used in the examples is available from Kelco under the trademark Kelzan.

[00011] The silicate resin promotes the adhesion of the sprayed lubricant to the hot forging dies and also acts as a binder. In the examples, Sodium Silicate N, available from Univar U.S.A. or Bedford Park, Illinois, is used.

[00012] The montmorillonite is a hydrous aluminum silicate clay that serves as a binder and thickener to maintain the graphite in suspension. In the examples, the montmorillonite is Clarsol FGN- FR 4 available from CECA in France.

[00013] The surfactant/defoamer is an ethylene oxide-propylene oxide copolymer that serves to inhibit settling and to reduce aeration during the formulation of the lubricant. In the examples, the surfactant/defoamer is Synperonic PE/L62, distributed by Univar U.S.A. Alternatively, Pluronic L62 surfactant/defoamer, also available from Univar U.S.A., may be used.

[00014] The cellulose thickener is hydroxypropyl cellulose. It serves as a binder and thickener and also as a water retention agent to retard the drying time of the lubricant so that it is not flashed awfully hot die. In the examples, the hydroxypropyl cellulose is Methocel KIOOLV, available from either MB Sveda, of Sweden, or Chemcentral, of Bedford Park, Illinois. [00015] The preservative for the high temperature lubricant is a mixture of two preservatives, namely a fungicide and an algaecide. In the examples, Bioban CS-1246 and Bioban P-1487, available from Sea-Land Chemical WestLake, Ohio, are used. [00016] The additional defoamer used in the high temperature lubricant also serves to reduce aeration during the formulation of the lubricant. In the examples, a proprietary defoamer, Dehydran 1922, made by Cognis and distributed by Fitz Chem Corporation, of Elmhurst, Illinois, is used.

Claims

IN THE CLAIMS :

1. A high temperature lubricant (adapted to be applied by an airless spray system) comprising: between about 50 wt . % and 90 wt . % water; between about 10 wt . % and 40 wt . % graphite; between about 1 wt . % and 10 wt . % montmorillonite; between about 0.1 wt.% and 5.0 wt . % xanthan gum; between about 0.5 wt . % and 2.0 wt . % of a surfactant/defoamer; and between about 0.5 wt.% and 2.0 wt.% of a preservative.

2. The lubricant of Claim 1 comprising: between about 75 wt.% and 85 wt.% water; between about 12 wt.% and 18 wt.% graphite; between about 3 wt.% and 4.5 wt.% montmorillonite; between about 0.1 wt.% and 2 wt.% xanthan gum; between about 0.1 wt . % and 0.5 wt . % of a surfactant/defoamer; and between about 0.1 wt.% and 0.5 wt.% of a preservative.

3. The lubricant of Claim 1 comprising: 80.00 wt.% water;

15.46 wt.% graphite; 3.80 wt.% montmorillonite; 0.30 wt.% xanthan gum; 0.24 wt.% surfactant/defoamer; and 0.20 wt.% preservative.

4. A lubricant of Claim 2 or 3 wherein the surfactant/defoamer comprises an ethylene oxide-propylene oxide copolymer, the preservative comprises glutaraldehyde, and the graphite comprises a synthetic graphite.

5. A high temperature lubricant (adapted to be applied by an airless spray system) comprising: between about 50 wt.% and 90 wt.% water; between about 10 wt.% and 40 wt.% graphite; between about 1.0 wt.% and 10.0 wt.% silicate resin; between about 1.0 wt.% and 10.0 wt.% dextrin; between about 0.1 wt.% and 10 wt.% of a cellulose thickener; between about 0.1 wt.% and 5.0 wt.% xanthan gum; between about 0.5 wt . % and 2.0 wt . % of a surfactant/defoamer; between about 0.5 wt . % and 2.0 wt.% of a preservative; and between about 0.5 wt.% and 2.0 wt.% of a defoamer.

6. The lubricant of Claim 5 comprising: between about 70 wt.% and 80 wt.% water; between about 12 wt.% and 18 wt.% graphite; between about 2 wt.% and 5 wt . % silicate resin; between about 4 wt.% and 7 wt . % dextrin; between about 2 wt.% and 5 wt.% of a cellulose thickener; between about 0.1 wt.% and 0.5 wt.% xanthan gum; between about 0.1 wt . % and 0.5 wt . % of a surfactant/defoamer; between about 0.1 wt . % and 0.4 wt.% of a combination of one or more preservatives; and between about 0.1 wt.% and 0.4 wt.% of a defoamer.

7. The lubricant of Claim 5 comprising: 72.7 wt . % water;

15.2 wt.% graphite;

3.2 wt.% silicate resin;

5.0 wt.% dextrin;

3.0 wt.% cellulose thickener;

0.3 wt.% xanthan gum;

0.2 wt.% surfactant/defoamer;

0.2 wt.% of a combination of two preservatives; and

0.2 wt.% of a defoamer.

8. The lubricant of Claim 6 or 7 wherein the silicate resin is a sodium silicate, the surfactant/defoamer is an ethylene oxide- propylene oxide copolymer; the graphite is synthetic graphite, the cellulose thickener is hydroxypropyl cellulose, and the preservative is a combination of oxazolidine and 4 (2-nitrobutyl) morpholine.