JPH0465151B2 - - Google Patents

Abstract

A heavy phosphate coating suitable as a base for a lubricant, prior to cold deformation of a ferrous surface, is formed by application of an aqueous acidic phosphating solution containing phosphate, organic nitro compound or nitrate (introduced as an inorganic nitrate), zinc, manganese or iron and, to increase the coating weight, hydroxylamine, is an amount of at least 0.01% by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to cold working of ferrous metals. More particularly, the present invention relates to a method of applying a lubricating phosphate coating to the surface of a ferrous metal and then cold working the metal.

[Prior art and its problems]

A metal phosphate conversion treatment solution is a diluted solution containing phosphoric acid and other chemicals that, when applied to a metal surface, reacts with the solution to form a substantially insoluble crystalline phosphate. A continuous coating layer forms on the metal surface. This layer is mainly applied for the purpose of preventing corrosion, but it can also be used as a base for a secondary coating (e.g. paint).
It can also be used as a vehicle to retain lubricants on chemically treated surfaces.

It is widely known that metal phosphate coatings are useful in metal processing. When a metal phosphate coating is applied to a metal surface immediately before processing, the friction between the metal surface and the die that occurs during drawing or cold working is significantly reduced.
The primary reason that phosphate coatings on metal surfaces reduce friction is due to the ability of the phosphate coating to uniformly retain a lubricant film on the metal surface. It is extremely important to impart this ability to the metal surface, and it is this secondary lubricant that suppresses metal-to-metal contact and reduces metal adhesion or "scratch" during cold working. It is from. This reduction in friction makes it possible to form the article by cold working, and without this reduction in friction, forming by cold working would be practically impossible or nearly impossible.

The present invention relates to a method of cold working ferrous metals by treating them with a phosphate chemical treatment solution that is particularly suitable for applying a lubricating or lubricant-retaining phosphate coating to the surface of the metal.

There are several prior art technologies regarding phosphate chemical treatment solutions containing hydroxylamine and film formation methods using the treatment solutions, and these technologies will be summarized below.

US Pat. No. 2,298,280 discloses the use of hydroxylamine in a phosphate conversion solution as an accelerator to promote the precipitation of a corrosion-resistant metal phosphate coating as a paint base. However, since the zinc and PO ₄ ^3- concentrations are relatively low and NO ₃ ^- is not present, the phosphate chemical treatment solution described in the examples of the publication is suitable for use in wires, for example.
For drawing of tubes, etc., it only provides a slightly effective lubricating film on the surface of these materials, and lubricating phosphorus is used immediately before performing cold working methods that are in demand, such as extrusion of large ferrous metals. This is completely inconvenient for the purpose of forming an acid salt film on the metal surface.

U.S. Patent No. 2702768 discloses sodium,
The use of hydroxylamine in amorphous phosphate coating solutions containing potassium and ammonium phosphates is disclosed.

US Pat. No. 2,928,762 discloses the use of hydroxylamine phosphate as a reducing agent in an orthophosphoric acid cleaning solution used in a preliminary cleaning step of a phosphate chemical treatment step.

U.S. Pat. No. 4,003,761 relates to a method for applying a phosphate film to iron-based surfaces, and this method involves adding 0.05 to 1.0 phosphate to an acidic aqueous solution with a pH of 4.3 to 6.5 containing an alkali metal salt or ammonium salt of phosphoric acid. g/
A method of spraying with an aqueous solution containing an oxidizing or reducing agent promoter and a lubricant, the promoter being a _C2 - _C4 alkanolamine is disclosed.

U.S. Pat. No. 4,149,909 discloses hydroxylamine sulfate as a hydroxylamine source for phosphate treatment compositions using hydroxylamine and chlorate/bromate mixing promoters.

U.S. Patent No. 4,220,486 discloses a chemical conversion treatment liquid with a pH of 5.5 to 6.5 containing 0.2 to 5.0 g/pyrazole, hydroxylamine, or hydrazine compound as an optional component; It is added to stabilize the . In these prior art hydroxylamine, hydroxylamine salts or complex salts are used only to aid in the deposition of phosphate coatings intended as paint bases or anti-corrosion bases. On the other hand, the present inventor has discovered that the phosphate film formed by medium to high film thickness chemical conversion treatment using a phosphate chemical treatment solution containing hydroxylamine is a phosphate film formed on the surface of iron-based metals immediately before cold working. They have found that it is particularly suitable as a lubricating or lubricant-retaining film. That is,
The presence of hydroxylamine in the phosphating solution, even in the presence of ferrous ions or the coexistence of ferrous and ferric ions, is particularly effective in pre-lubricating the surface of ferrous metals immediately before cold working. It has been found that suitable metal phosphate coatings can be deposited.

[Object of the present invention]

An object of the present invention is to provide a method for cold working a ferrous metal by applying an improved lubricating film to the surface thereof. The benefits and advantages of the present invention can be achieved by forming a metal phosphate coating on the ferrous metal surface with a phosphate conversion solution containing hydroxylamine.

[Structure of the invention]

The present invention is capable of treating iron-based metals by surface-treating them using an acidic phosphate chemical treatment solution containing a certain amount of hydroxylamine, which is effective for increasing the precipitation rate of metal phosphate coatings. It consists of applying a lubricating phosphate film to the surface of the metal, followed by cold working.

In a preferred embodiment, the phosphate coated ferrous metal is further contacted with a secondary lubricant prior to cold working. In addition to PO ₄ ^3- , this chemical conversion treatment solution contains zinc, manganese, nitric acid, nickel, ferrous and ferrous iron.
It is preferable to contain one or more ions selected from the group consisting of iron, copper, fluoride, and mixtures thereof.

Prior to phosphate treatment, ferrous metals are cleaned,
It may be subjected to one or more known pretreatment steps such as pickling, water rinsing, and other steps. After phosphate treatment, the ferrous metal can also be subjected to one or more post-treatment steps such as neutralization, water rinsing, drying, etc. before cold working. After the chemical conversion treatment, it is also possible to perform a secondary lubrication process. Unique lubricity is imparted through chemical conversion treatment with medium or high film thickness, so
As a result, cold working efficiency can be improved.

Other benefits and advantages will become apparent from the detailed description of the invention included in conjunction with the examples.

[Action of the invention]

The cold working method of the present invention utilizes a high quality lubricating phosphate coating.

The lubricating phosphate film used in the present invention is deposited on the surface of a ferrous metal just before cold working, and this film is extremely suitable for providing lubricity during cold working. The unique properties of this coating are based on its (1) ability to provide lubricity during cold working and/or (2) secondary lubrication ability or ability to retain lubricant. Although the terms cold working and cold deforming are used synonymously, both terms refer to the process of processing a metal, such as a blank, slag, or preform, below its recrystallization temperature.
Preferably, it means deformation work at a temperature of 100°C or less. Therefore, the temperature increase mainly refers to work that occurs naturally due to friction during deformation, work hardening, etc. Specifically, the term refers to cold extrusion, cold heading, and wire tube drawing.

The unique coating of this invention is applied with a phosphate treatment solution. The phosphate conversion treatment solution used in the present invention contains a number of additives, except that the solution contains as an essential component an amount of hydroxylamine as an accelerator effective to increase the rate of precipitation of the lubricating phosphate film. In this respect, it is the same as the known phosphate chemical treatment solution. The presence of hydroxyamines imparts unique properties to the coating that are extremely useful during cold working. In accordance with the practice of the present invention, ferrous metals, such as blanks, slags, or preforms, can be treated with an acidic phosphate treatment solution containing an effective amount of hydroxylamine to provide a unique coating.

Iron-based metals to which the method of the present invention can be applied are those that can be deformed at a temperature below the recrystallization temperature. Particularly preferred metals have a carbon content of about 1.0% by weight or less;
Preferably from about 0.05 to about 0.6% by weight steel product.
Furthermore, even when the improved lubricity phosphate coating of the present invention is applied to steels that are difficult to work due to their high alloying ratio or high hardness, they can be cold worked.

As the hydroxylamine source added to the phosphate chemical treatment solution, any known type of hydroxylamine source can be used, but hydroxylamine salts or their complex compounds with good storage stability are preferred; many of these are commercially available as hydrates. has been done. More preferred is hydroxylamine sulfate ("HAS"), a stable salt of hydroxylamine.

Hydroxylamine sulfate has the formula (NH ₂ OH) _{2.H 2} SO ₄ or (NH ₃ OH) _{2.SO 4} .

An effective amount of hydroxylamine is used in the phosphate chemical treatment solution of the present invention, and this "effective amount"
The term refers to an amount of hydroxylamine sufficient to facilitate the conversion process regardless of the type of hydroxylamine source. That is, when comparing substantially the same phosphate conversion treatment solutions, one containing hydroxylamine and the other not, the solution containing hydroxylamine forms a greater coating weight for a given treatment time; It has the ability to build up weight faster.

The phosphate chemical treatment solution used in the present invention is approximately 0.01
Contains hydroxylamine in a concentration of ~10% by weight; if the solution used is primarily an aqueous solution with a specific gravity of about 1, the above weight% can be directly replaced by weight/volume%. The hydroxylamine concentration present in the phosphate chemical treatment solution of the present invention ranges from about 0.01 to about
3.0%, more preferably in the range of about 0.05 to about 1.0%.

When hydroxylamine is present in the phosphate chemical treatment solution used in the method of the present invention, the amount of metal (especially zinc) in the resulting film increases, improving the physical properties of the film and also improving the lubricant storage stability. it is conceivable that. Therefore, the lubricity of the phosphate crystal itself improves, but in this case, when the zinc content in the coating increases, the primary lubricating phosphate coating is applied over the secondary phosphate coating. Increased ability to react with fatty acids and fatty acid soaps in lubricants. For example, when a zinc phosphate coating comes into contact with a secondary lubricant containing sodium or potassium stearate, the zinc in the coating reacts with the stearate groups. The zinc stearate produced here has a better lubricating effect than sodium stearate. If more zinc is included in the film, more zinc stearate will be formed on the film. Thus, an increase in zinc stearate significantly increases the surface's ability to retain a secondary lubricant, which in conjunction with the lubricity of zinc stearate significantly improves the lubricity.

In the method of the present invention, the phosphate treatment solution used contains zinc, manganese, or a mixture thereof, and among these, the so-called high zinc phosphate treatment solution is particularly preferred. The zinc concentration of the zinc-containing phosphate conversion solution is about 0.25 to about 7.5% by weight, more preferably about 0.75 to about 5.5% by weight, and most preferably about 1.0 to about 3.0% by weight.

In the practice of the present invention, the concentration of PO ₄ ^3- ions in the phosphate chemical treatment solution is preferably about 0.5 to about 8.0% by weight, more preferably about 1.0 to about 7.0% by weight, and most preferably about 2.0 to about 4.0% by weight. %. These values can also be expressed as weight as [PO ₄ ^3- ] per weight of solution.

Additionally, the phosphate chemical treatment solution suitable for use in the present invention contains about 0.5 to about 10 NO ₃ ^- ions.
% by weight, preferably in the range of about 1.0 to about 7.5% by weight. In a more preferred embodiment, about
Contains a concentration of 3.0 to about 7.0% by weight.

When NO ₃ ^- ions and PO ₄ ^3- ions coexist in the phosphate chemical treatment solution used in the present invention, the value obtained by dividing the NO ₃ ^- ion concentration by the PO ₄ ^3- ion concentration, that is, [ The value of NO ₃ ^- ]/[PO ₄ ^3- ] is
Preferably about 0.3 to about 6.0, more preferably about 0.5
to about 5.0, most preferably about 0.9 to about 4.5.

One of the characteristics of the phosphate chemical treatment solution used in carrying out the present invention is that it has the ability to deposit a film containing a high concentration of zinc even in the presence of ferrous and ferric ions. It is. Preferably, the concentration of ferrous ions, if present, ranges from about 0.05 to about 0.6% by weight. If ferric ions coexist, the concentration of ferrous ions must be accurately measured.

The weight of the lubricating phosphate coating applied to the surface of the ferrous metal used in the cold working of the present invention depends on the severity of the cold working conditions, the size of the metal article, and other factors. Although this may vary, other factors include factors such as whether or not to apply a secondary lubricant, and the type of lubricant. The applied coating weight is approximately 2.7 to approximately 64.5 g/ ^m2 (approximately 0.25 to approximately 6 g/m2).
^ft2 ) range. Approximately 3.8 to approximately 48.4g/m ² (approximately 0.35
More preferably, the range is from about 5.4 to about 37.6 g/ ^ft2 (about 0.5 to about 3.5 g/m2), and most preferably from about 5.4 to about 37.6 g/ ^m2 .
g/ft ² ).

In another preferred embodiment, the phosphate conversion solution contains nickel. A preferred concentration of nickel is from 0 to about 0.1% by weight, more preferably from about 0.01 to about 0.05% by weight.

In a preferred embodiment, when treating iron-based metals with the phosphate chemical treatment solution used in the cold working of the present invention, the solution temperature is about 54 to about 96 °C (about 130 to about 205 °C),
Preferably, the temperature is maintained at about 71 to about 88°C (about 160 to about 190°C), and the pH of the solution is preferably maintained at about 1.8 to about 2.5.

The phosphate chemical treatment solution can be applied by a conventional method. It can be carried out by dipping or pouring, but the dipping method is particularly preferred. Immersion times range from about 0.5 to about 30 minutes, with about 5 minutes to about 15 minutes being particularly preferred.

After treating the surface of the iron-based metal with this phosphate chemical treatment solution, it is desirable to neutralize it by rinsing it with a weakly alkaline aqueous solution.

The coated metal to be cold worked is preferably contacted with a conventional secondary lubricant. This operation may be carried out immediately after the chemical conversion treatment (or rinsing) on the press side immediately before cold working, or may be carried out during the cold working process.

Secondary lubricants include fatty acid soaps, oils, drawing lubricants, emulsions of oil and fatty acids, or fatty acid salts. The secondary lubricant preferably contains about 3 to 15% by weight of a _C8 to _C18 fatty acid or fatty acid salt or fatty acid soap, more preferably selected from sodium stearate, potassium stearate, and mixtures thereof. It contains fatty acid soap.

As mentioned above, fatty acid soaps are preferred components because of their ability to react with the high concentrations of zinc in the phosphate coatings used in the present invention. The resulting zinc hydroxystearate is an excellent lubricant for cold working. For drying after treatment with fatty acid soap, known methods such as hot air drying or flush drying are effective. However, if the metal to be treated is contaminated with oil or the like, or has rust, scale, etc. attached, the surface must be cleaned by appropriate cleaning means before the present invention is applied.

Metal articles treated with the method of the present invention may be subjected to post-treatment steps either prior to application of the secondary lubricant or prior to cold working, or both. For example, a preferred method is to immediately neutralize the phosphate coated article with a dilute chromium-free alkaline rinse solution. A weakly alkaline aqueous solution containing borates, nitrites, triethanolamine, or mixtures thereof may be used for such rinsing purposes.

In the most preferred embodiment, the metal article (1)
(2) hot water rinsing; (3) treatment with a phosphate treatment solution containing an effective amount of hydroxylamine; (4) cold water rinsing; These steps include (5) rinsing with a weakly alkaline aqueous solution, (6) treatment with a secondary lubricant consisting of sodium stearate, and (7) flush drying.
It is then subjected to cold working immediately or after storage until cold working is required.

〔Example〕

The effects of the present invention will be explained in more detail with reference to Examples.

Example 1 This example discloses a method for preparing a phosphate chemical treatment solution used in the present invention and a method for using the same.

Contains 4.05 wt% zinc, 5.00 wt% _PO4 , 5.55 wt% _NO3- ions, 0.01 wt% Ni, total acidity 60 points ( ^10.0ml sample was 0.1N NaOH using phenolphthalene indicator) The total acid point is 0.1NNaOH required to titrate to the end point.
A freshly prepared phosphate treatment solution (equal to 180 mL) was heated to 82 °C (180 °C). Hydroxylamine sulfate (HAS) immediately after reaching 82°C
5.0g/(0.5% by weight) was added. After standing for 5 minutes to reach equilibrium, 0.007% by weight of sodium nitrite (NaNO ₂ ) was added. After another 5 minutes, 10cm (4 inches) x 15cm (6 inches) x 36cm
(14-inch) gauge pickled cold-rolled steel specimens were immersed two at a time for 5 minutes every 10 minutes [approximate processing load rate (phosphate treatment load rate)]
9.3dm ² (treatment area) / hr・(3.8ft ² /hr・
gal.)〕. The weight of the phosphate coating is 2 compared to the case of phosphate treatment under the same conditions except that it does not contain HAS.
It was possible to stably form a film with a high film weight without showing a tendency for the film weight to increase twice as much, and the film weight did not show a tendency to rapidly decrease. The crystal morphology and crystal composition of the phosphate coating are the same when HAS is used, and the P-ratio of the coating [phosphophyrite/phosphophyllite+ measured by X-ray crystallography method] hopite] showed a value of 0.105.
On the other hand, the P-ratio of the phosphate film formed when HAS was not used was 0.165.
The low P-ratio of 0.105 indicates that the zinc content in the phosphate film is at a high level applicable to the present invention. [However, HAS
When a film was formed with a phosphate chemical treatment solution containing phosphate and then treated with a secondary lubricant approximately 30 days later, the reactivity between the zinc in the phosphate film and the soap lubricant clearly decreased. was. The article treated with the solution described above is then subjected to a conventional weak alkaline rinse and allowed to sit for a suitable period of time (up to about 5 hours) before being applied with a secondary lubricant containing sodium stearate. After application of the secondary lubricant, the article was flash dried and the article was then subjected to conventional extrusion with excellent results.
Such articles could be subjected to cold working processes more efficiently than articles treated with known phosphate conversion treatment solutions.

Example 2 A concentrated solution of phosphate chemical treatment solution used in the method of the present invention was prepared according to the following formulation.

Concentrated liquid A component weight parts Water 360.5 ZnO (80.3% Zn) 159.0 Nitric acid (42° Be′ 67% HNO ₃ ) 255.5 Phosphoric acid (75% H ₃ PO ₄ ) 216.7 Hydroxylamine sulfate 6.0 Nickel nitrate (13.9% Ni ;29.3%NO ₃ ) 2.3 1000.0 Next, this concentrated liquid A is diluted with water to prepare a treatment liquid. The bath is prepared by diluting 79.4 Kg (175 lbs) of Concentrate A with water to make a total volume of 378 (100 US gallons) solution. That is, per treatment liquid
210g of concentrated liquid A is required.

The processing solution prepared from concentrated solution A can be reactivated by replenishing the next concentrated solution B during use.

Concentrated liquid B component weight parts Water 302.2 ZnO (80.3% Zn) 132.3 Nitric acid (42° Be′ 67% HNO ₃ ) 143.1 Phosphoric acid (75% H ₃ PO ₄ ) 400.8 Nickel nitrate (13.9% Ni; 29.3% NO ₃ ) 1.6 Hydroxylamine Sulfate 20.0 1000.0 This concentrate B can be used as a replenisher when the total acid:free acid ratio of the processing solution exceeds the desired level, but if the ratio falls below the desired level. If the processing liquid is contaminated, the processing liquid is reactivated by replenishing the processing liquid with concentrated liquid A.

Claims (1)

[Scope of Claims] 1. A method for lubrication treatment before cold working of ferrous metals, which includes the following steps: (a) The surface of ferrous metals is coated with PH1.8 containing the following components:
~2.5 to form a phosphate film on the surface: Zn 0.25 to 7.5% by weight PO ₄ ^3- 0.5 to 8.0% by weight NO ₃ ^- 0.5 to 10.0% by weight Hydroxylamine 0.01 ~10.0% by weight [ _NO3 ^- ]/[ _PO43- ] 0.3-6.0 (b) ^The surface of the iron-based metal on which the phosphate film is formed is coated with 3-15% by weight of _C8 - _C18 fatty acids, fatty acids. salt,
A lubrication treatment method for cold working of ferrous metals, characterized in that the treatment is performed with a lubricant containing a fatty acid soap or a mixture thereof.