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Mapping and development of alternatives to chlorinated lubricants in the metal industry (KLORPARAFRI)

5 Mapping of alternative lubricants

• 5.1 Method
• 5.2 Results

5.1 Method

In order to get an overview of non-chlorinated metal forming lubricant technology available on the international market, contact has been made to a number of companies in Europe and the US. These are mainly larger companies with expertise in the field of metalworking lubricants and extreme pressure additives. However, there are also a number of smaller, highly specialized companies. Some of the companies contacted are Castrol, Henkel Surface Technologies, Master Chemical Cooperation, Klüber Lubrication, Houghton, Holifa, Rhenus Lub, Vulcan Oil & Chemical Products, Pfau Oil Products, Fuchs DEA Schmierstoffe, Uniqema, Chemetall, Quaker Chemical, Rocol Lubricants, Hangsterfers and Dover Chemical Corporation.

In addition, contact has been made to a large steel supplier, Avesta Polarit. This in order to clarify whether pre-coated steel plates are being marketed. The purpose of the pre-coating of steel plates should be to diminish or remove the demand for lubrication in the subsequent manufacturing processes.

The lubricant suppliers have been asked about lubricants for deep drawing, several step deep drawing, stamping, several step stamping, extruding, several step extruding and calibration as well as ironing in stainless steel, acid-proof steel, titanium, alloys and metal combinations – e.g. coatings (see also chapter 2).

Not only the process type and material define the technical demands to a metal working lubricant. Also tools and application and washing conditions influence the ultimate technical suitability of a lubricant. However, mapping of alternative lubricants has mainly focused on compliance with technical demands for the core property of the lubricant, namely the lubricating ability in specified processes. Demands for application and washing etc. are considered to be secondary properties of the lubricant, for which it is most often possible to subsequently adjust.

Contact to lubricant and additive suppliers has been made in two steps. In step one, a request is made to the suppliers for non-confidential sales information such as use, technical suitability and capacity, physical/chemical data, application, washing and removal as well as a material safety data sheet. Based on the information obtained, an evaluation has been made of the technical suitability of the lubricants for the manufacturing processes that are the focus of the project. In step two, contact has been made to the suppliers who, based on the forwarded information, will possess promising alternative lubricants. This step to obtain information on product composition including any data on effects on health and environment.

The lubricants suggested are divided into categories with regard to suitable manufacturing processes and materials, type of lubricant based on chemical composition and application of the lubricant.

For manufacturing processes and materials, the following categories are used:

A Deep drawing, unspecified
A1 Deep drawing in high alloy steel (> 4% Cr)
A2 Deep drawing in aluminium
A3 Deep drawing in other metals

B Stamping, unspecified
B1 Stamping in high alloy steel (> 4% Cr)
B2 Stamping in aluminium
B3 Stamping in other metals

C Extruding, unspecified
C1 Extruding in high alloy steel (> 4% Cr)
C2 Extruding in aluminium
C3 Extruding in other metals.

With regard to type of lubricant, the lubricants are categorized according to their basic content.

Basic content:

1. Pure mineral oil
2. Solvent based liquid
3. Emulsion of mineral oil
4. Semi-synthetic liquid
5. Synthetic oil
6. Pure vegetable oil and/or animal oil
7. Emulsion of vegetable and/or animal oil.

Type 1 are lubricants based on various mineral oil fractions and free from water. The agents are used undiluted.

Type 2 are solvent-based lubricants, free from water and used undiluted. The agents have a high content of solvents.

Type 3 are emulsifiable lubricants with a mineral oil content of 20-30 %. The agents are used diluted with water.

Type 4 are semi-synthetic lubricants with a mineral oil content of less than 10-15 %. The agents are used diluted with water.

Type 5 are lubricants based on synthetic oils and free from mineral oil. The agents may be diluted with water prior to use.

Type 6 are lubricants based on vegetable and/or animal oils and free from water. The agents are used undiluted.

Type 7 are emulsions of vegetable and/or animal oils. The agents do not contain mineral oil and should usually be diluted with water.

In addition, the lubricants have been categorized as dry lubricants (D) or wet lubricants (W), respectively depending on the type of application. See also chapter 2.

5.2 Results

In step 1 of the mapping phase, contact has been made to approximately 50 international companies marketing either metal working lubricants or lubricant additives. Of these, 16 companies have forwarded suggestions for approximately 60 alternative lubricants based on technical specifications on manufacturing processes and materials. As contact has been made to suppliers of both lubricants and EP additives, the suggestions for alternative lubricants include finished products (off-the-shelf items) as well as products requiring a certain production maturation.

A technical examination of the forwarded product information assessed that 15 of the 16 suppliers should possess lubricants that have a potential for being technically suited for the processes and materials described in chapter 2. The result of step 1 of the mapping phase is stated below in table 5.1. As can be seen from the table, 53 products are estimated as potential alternatives to chlorinated lubricants in the processes specified. Seven of the initially proposed lubricants are not included in table 5.1 due to failure in complying with technical criteria established in step 1 of the technical assessment of proposed lubricants.

Table 5.1 Overview of proposed alternative lubricants for the metal working processes in focus and described in chapter 2. An * indicates that use of the lubricant in question depends on a preceding phosphating or oxalating of the metal surface.

W indicates a wet lubricant, D indicates a dry lubricant. See also chapter 2.

As can be seen from table 5.1, it varies how specifically the supplier has stated the processes suitable for the lubricants.

Most of the lubricants suggested are traditionally formulated as wet lubricants similar to chlorinated lubricants. Six lubricants are dry lubricants which means that a drying step is needed in the manufacturing process, see also chapter 2. Two proposed lubricating systems marked with an * require a preceding phosphating or oxalating of the metal surface prior to lubrication, see also chapter 2. Wet lubricants are the dominating type of lubricants.

As regards chemical composition, the majority of the lubricants suggested are based on either synthetic esters, polymers or on mineral oil. However, virtually all types of lubricants are represented, including a solvent-based lubricant – type 2. The last-mentioned was dropped in step 1 of the mapping phase due to a low flash point (< 100°C).

Table 5.2. Overview of suggested alternative lubricants that are subsequently tested in the simulating test in step 2 as described in section 5.1.

In step 2 of the mapping process, contact has been made to the 15 suppliers who, based on the information forwarded, are in a position to offer lubricants that are technically suitable for demanding forming operations in high alloy steel and other metals, as specified in section 5.1. Product samples for testing and detailed composition information for the relevant products are requested at this stage.

As can be seen from table 5.2, 11 suppliers have forwarded a total of 19 lubricants for testing. Of the 19 proposed lubricants, sufficient information regarding the chemical composition has been received for 15 lubricants in order to perform the health and environmental assessments of lubricants and selected lubricant components. Despite our request for non-chlorinated lubricants, one product turned out to contain polychlorinated alkanes. This product was dropped. One dry lubricant is represented among the 15 products. Lubricants based on mineral oil, synthetic esters as well as vegetable and animal oils are represented.

As mentioned in section 5.1, contact has also been made to a large supplier of steel during step 1 of the mapping phase. The supplier has been contacted in order to clarify whether a preceding coating of steel plates can take place and function as a lubricant in the subsequent metal working processes or reduce the demand for subsequent lubricants. The result was that no coating of steel plates takes place prior to resale to remove or reduce the need for lubricants during steel work. No efforts are being made to develop such processes (12).

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Version 1.0 October 2005, © Danish Environmental Protection Agency