CA1113916A

CA1113916A - Lubricant for plastic working

Info

Publication number: CA1113916A
Application number: CA320,873A
Authority: CA
Inventors: Torao Nagura
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 1978-02-07
Filing date: 1979-02-06
Publication date: 1981-12-08
Also published as: GB2016039B; JPS54105651A; FR2416258A1; DE2905046A1; GB2016039A

Abstract

Abstract of the Disclosure:

A lubricant for plastic working which is positively free of oily matter is prepared by adding a solid powder lubricant to a polyhydric alcohol.

Description

This invention relates to a novel lubricant for plastic working, especially for pipe expanding, which is positively free of oily matter and is soluble in water.
Generally, in the manufacture of boilers, a lubricant such as a mineral oll, animal or vegetable oil, grease or the like is employed for the expansion of boiler tubes.
Such oily matter must be thoroughly removed befoxe the start o~ boiler operation. This end has usually been accomplished by a degreasing and cleaning method that relies on so-called soda cooking, in which the oily matter is emulsi~ied for subsequent removal with the addition of a large quantity of sodium hydroxide, sodium carbonate, sodium phosphate, sodium sulfite or the like and by boiling together up to a predetermined pressure.
The ordinary degreasing method has, however, had shortcomings of much cost and labor requirementsO In addition, the resulting waste liquid that contains oily matter cannot be discharged after a mere neutralizing treatment, but it should be cleaned to the local effluent standard value for environmental protection (an oil content of not more than 5 ppm or, in some districts, not mor~ than 1 ppm). The treatment of waste liquid up to this cleanliness invol~es enormous cost.
A more recent trend in the art is to use a water-solub~ cutting oil as the lubricant in order to simpli~y the process of degreasing and cleaning. The used cutting oil is thoroughly washed away by hot water or hydrazine but, because the waste liquid still contains oily matter, the disadvantage in the disposal of the waste remains unremoved.

~39~1L6 In view of the foregoing, the present invention is aimed at the provision of a novel lubricant for plastic working which necessitates no degreasing or cleaning and therefore no waste liquid treatment.
In brief, the lubricant according to the invention consists of a solid powder lubricant added to ~ pGlyhydric alcohol.
Useful polyhydric alcohols for the invention are those capable of attaining lubricating effects, for ex~mple, glycerol, ethylene glycol, diethylene glycol, trie~hylene glycol, propylene glycol, dipropyl~ne glycol, butylene glycol, and hexylene glycol, and other highly viscous alcohols. Such a polyhydric alcohol is desirably used in a proportion ranging from 50 to 80% by weight of the total amount of the lubricant for plas~ic working according to the invention.
The solid powder lubricant to be added to the polyhydric alcohol is one that improves the workability as well as the lubricity of the resulting lubricant.
Examples of such additives are talc, molybdenum disulfide, and graphite. Desirably the additive accounts for from 20 to 50~ by weight of the total amount of the lubricant for plastic working~ The solid powder lubricant may be any of the common ones commercially available.
The lubricant of the invention for plastic working is prepared simply by mixing such a solid powder lubricant with a polyhydric alcohol at ordinary temperature.
When it is used for pipe expanding, the lubricallt according to the invention is applied in advance on the sliding surfaces (i.e., on the pipe expanding parts) of 391~

the expander. For this application the lubrican-t of the invéntion, in the form of a highly viscous liquid or pas-te free of any addition agent for that puxpose, is most advantageous, because the vis~osity is usually desirable for such a lubricant to act effec~ively on those surfaces without the loss due to flow from the surfaces to be luhxicated.
Although the lubricant according to the invention has been descri~ed as used in the expanding of tubing for boilers, it should be obvious to those skilled in the art that the lubricant may be applied to the expanding for the manufacture of heat exchangers and other apparatus and also to plastic working of metals in general.
The lubricant of the invention for plastic working ~, 15 is (1) positively free of oily matter,

(2) neutral and soluble in water, and

(3) low in chemical oxygen demand and suspended matter.
Therefore, when employed in the manufacture of a boiler, the lubricant eliminates the necessity of degreasing and washing before the initiation of boiler operation.
Hence no problem of water li~uid di~posal and remarkable reductions in the personnel expenses, number of man-hours, chemicals cost, and total working time required for the manufacture.
Further, the lubricant of the invention for plastic working has additional advantages of

(4) sanitariness with no toxicity or offensive 3Q odor, 3~

(5) applicability with u-tmost ease, (6~ economy in application without loss due to flow rom the surface, and (7~ sufficiently good lubricity to ensure exactly the same facility and finish of pipe expanding as with ordinary lubricants.
The present invention is illustrated by the examples tabulated below, in which all parts are given by weight.
E x a m p 1 e s _ Solid powder ~
Polyhydrlc alcohol lubricant Applicability &
No. _ workability in ~thylene Propylene Molybdenum pipe expanding glycol glycol Talc disulfide ~.- _ 1 50 20-50 Good 3 50 20-50 ~
~ 50 ~ "

In experiments for reference the solid powder lubricants alone were employed for pipe expanding.
The results were very unsatisfactory with poor applic-ability and workability. The solid lubricants, when impasted with starch, caused in convenience by sticking ast ~o the surfaces of the expander.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In the manufacture of boilers having boiler tubes therein including expanding the boiler tubes by means of tube expanding parts to sliding surfaces of which a lubricant has been applied the improvement in which the lubricant is positively free of oily matter and comprises a mixture of a solid powder lubricant and a polyhydric alcohol.

2. A method according to claim 1, in which the lubri-cant is composed of from 80 to 50% by weight of said polyhydric alcohol and from 20 to 50% by weight of said solid powder lub-ricant.

3. A method according to claim 1 or 2, in which said solid powder lubricant is at least one of the lubricants selected from the group consisting of talc, molybdenum disulfide, and graphite.

4. A method according to claim 1 or 2 in which said polyhydric alcohol is at least one of the alcohols selected from the group consisting of glycerol, ethylene glycol, di-ethylene glycol, triethylene glycol, propylene glycol, dipropyl-ene glycol, butylene glycol, and hexylene glycol.

5. A method according to claim 1 or 2 in which said solid powder lubricant is at least one of the lubricants selected from the group consisting of talc, molybdenum di-sulfide, and graphite and said polyhydric alcohol is at least one of the alcohols selected from the group consisting of glycerol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, diproylene glycol, butylene glycol, and hexylene glycol.