EP0169413A2 - Pickling composition - Google Patents

Abstract

Pickling agent for pickling iron or steel workpieces to be rolled in the range of rolling temperatures from 600 to 1300 ° C. The agents contain an active substance, a lubricant and optionally an antioxidant, a substance which controls the physical properties and a reductive substance. The components can be selected so that the mordant has a pronounced pickling or lubricating or antioxidant effect.

Description

The invention relates to a means for pickling, for lubrication and as an antioxidant for workpieces made of iron and steel in hot cutting without cutting.

When manufacturing sheet metal by rolling, profiles in profile rollers or seamless tubes on shaping bench systems, step rolling mills, Asselstrasse, stopper rolling mills, continuous streets, pilgrimage streets or multiple pipe mill systems, upsetting presses or extrusion presses, the surfaces that have to be processed, for example in hollow blocks, have to be processed , Blanks or tubes, the tube inner walls, are pickled before rolling in order to limit tool wear and to give the resulting workpiece a good surface finish.

Experience has shown that a smooth surface can only be achieved if the workpiece has been descaled or pickled before it is deformed. The pickling can be done mechanically or with the help of pickling baths, e.g. aqueous acid solutions, with salt baths made of sodium hydroxide, sodium hydride or metallic sodium. Solid mordants consisting of mixtures of sodium sulfate and phosphoric acid have also been used. Another suggestion was to remove the scale by applying molten mixtures of water glass and soda with borax or phosphates, which should detach the scale from the workpiece surface when it cools.

All of these processes and the descaling and pickling agents used for them are unable to meet the requirements placed on the pickling agents, in particular in a system for producing seamless tubes, but also in modern rolling and profile rolling mills.

For example, in the manufacture of seamless pipes on the aforementioned systems, the pickling agent must be brought into the cavity of the workpiece at the rolling temperature and distributed evenly within the work cycle and in periods down to 1 second, with the aim of achieving quick and safe pickling in order to then immediately to be able to roll out the workpiece.

The object of the invention is to describe a pickling agent that can be used at temperatures of over 600 to 1300 ° C. and enables quick and reliable pickling

According to the invention this is achieved with a pickling agent according to claim 1.

• Na₂B₄O₇ . 10H₂O;
• Na₂B₄O₇ . 5H₂O;
• ^Na ₂ ^B ₄0₇ wasserfrei;
• Natrium-Metaborat, NaB0₂ . 4H20;
• Borsäure, ^H ₃ ^B0 ₃;
• _Borsäureanhydrid, B₂ ⁰ ₃;
• lösliches Natriumsilikat mit einem SiO₂/Na₂O-Verhältnis
• von 2,5 bis 3,3 und
• Natriummetasilikat, Anhydrid oder mit 5 und 9 Kristallwasser.

The substances in group a) are the active pickling agents which chemically convert the predominantly oxidic scale constituents. This group includes:

• Na ₂ B ₄ O ₇ . 10H ₂ O;
• Na ₂ B ₄ O ₇ . 5H ₂ O;
• ^Na ₂ ^B ₄ 0 ₇ anhydrous;
• Sodium metaborate, NaB0 ₂ . 4H20;
• Boric acid, ^H ₃ ^B0 ₃ ;
• _B orsäureanhydrid, B ₂ ⁰ _3;
• soluble sodium silicate with a SiO ₂ / Na ₂ O ratio
• from 2.5 to 3.3 and
• Sodium metasilicate, anhydride or with 5 and 9 water of crystallization.

• Graphit;
• Calciumfluorid;
• _Kryolit, Na₃ ^Al ^F ₆;
• _Antimonoxid, Sb₂O₃:
• 15Molybdändisulfid, MoS₂;
• Bornitrid, BN;
• eines der Phosphate aus der Reihe
• Trinatriumphosphat, hydratisiert oder nicht hydratisiert
• Trikaliumphosphat, hydratisiert oder nicht hydratisiert
• ONatriummetaphosphate (NaP03)3 und (NaPO₃)₄;
• Kaliummetaphosphat (KPO₃)₃ und (KPO₃)₄;
• Polymetaphosphat (NaPO₃)₄. ^H ₂ ⁰;
• Natriumtripolyphosphat Na₅P₃0_10' hydratisiert oder nicht hydratisiert,
• 5Natriumpolyphosphat (Na₅P₃O₁₀)_2-8 und Zinkphosphat (PO₄)₂Zn₃.

The substances mentioned in group b) act as solid lubricants under the prevailing temperature and pressure conditions. These solid lubricants remain on or in the workpiece and are used for lubrication during the subsequent rolling operation. This group includes:

• Graphite;
• Calcium fluoride;
• _K ryolit, Na ₃ ^A l ^F _6;
• _A ntimonoxid, Sb ₂ O _3:
• 15 molybdenum disulfide, MoS ₂ ;
• Boron nitride, BN;
• one of the phosphates in the series
• Trisodium phosphate, hydrated or not hydrated
• Tripotassium phosphate, hydrated or not hydrated
• ONodium metaphosphates (NaP03) 3 and (NaPO ₃ ) ₄ ;
• Potassium metaphosphate (KPO ₃ ) ₃ and (KPO ₃ ) ₄ ;
• Polymetaphosphate (NaPO ₃ ) ₄ . ^H ₂ ⁰ ;
• Sodium tripolyphosphate Na ₅ P ₃ 0 _{10 '} hydrated or not hydrated,
• 5 sodium polyphosphate (Na ₅ P ₃ O ₁₀ ) _2-8 and zinc phosphate (PO ₄ ) ₂ Zn ₃ .

The polymetaphosphates mentioned also include compounds known under the names Madrell's salt, Graham's salt and Kurrol's salt.

• Koks, pulveriger Kohlenstoff,
• Cellulose in Pulverform, Sägemehl,
• Stärke und deren Derivate,
• Paraffine, Wachse,
• Fettsäuren und/oder Salze davon,
• Kolophonium und dessen Derivate,
• synthetische Harze auf der Basis von Kohlenwasserstoffen
• mit 5 bis 10 C-Atomen, Terpen-Harze und Inden-Cumaron-Harze.

The substances according to group c) cause the formation of a uniform layer on the surfaces to be treated, both in terms of their thickness and the homogeneity of the various components. This is achieved through the melting behavior and the film-forming properties of the substances mentioned below. At the same time, the substances according to c) have an important antioxidant effect. This group includes:

• Coke, powdery carbon,
• Powdered cellulose, sawdust,
• Starch and its derivatives,
• Paraffins, waxes,
• Fatty acids and / or salts thereof,
• Rosin and its derivatives,
• synthetic resins based on hydrocarbons
• with 5 to 10 carbon atoms, terpene resins and indene-coumarone resins.

Synthetic resins based on hydrocarbons with 5 to 10 carbon atoms are understood to mean the so-called "hydrocarbon resins" and in particular the "petroleum resins" as defined in Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd edition, Volume 12, pages 852-861.

• Natriumchlorid,
• Kaliumchlorid,
• Calciumchlorid,
• Natriumsulfat,
• Natriumacetat,
• Kaliumacetat und
• Tone.

The series of substances according to group d) influences the physical properties of the mordant, in particular the melt viscosity and the melting point. This group includes: Magnesium chloride MgCl ₂ . 6H20,

• Sodium chloride,
• Potassium chloride,
• Calcium chloride,
• Sodium sulfate,
• Sodium acetate,
• Potassium acetate and
• Tone.

• Ammoniumchlorid NH₄C1,
• Harnstoff CO(NH₂)_2'
• Ammoniumcarbonat (NH₄)₂CO₃,
• Harnstoff-Formaldehyd-Harz,
• Natriumcarbonat Na₂CO₃.

The series of substances according to group e) serve to reduce the oxides formed and during the pickling process and at the same time develop a separating effect due to their thermal decomposition and the resulting gas formation. This group includes:

• Ammonium chloride NH ₄ C1,
• Urea CO (NH ₂ ) _{2 '}
• Ammonium carbonate (NH ₄ ) ₂ CO ₃ ,
• Urea-formaldehyde resin,
• Sodium carbonate Na ₂ CO ₃ .

• 20 bis 80 Gew.% a)
• 1 bis 80 Gew.% b)
• und 0 bis 79 Gew.% eines oder mehrerer Stoffe aus jeweils einer oder mehrerer der Gruppen c), d) und e), wobei 0 bis 35 Gew.% c)
• 0 bis 50 Gew.% d) und
• 0 bis 5 Gew.% e) enthalten sind.
• Zweckmässig lauten die Mengenangaben
• )20 bis 65 Gew.% a)
• 5 bis 75 Gew.% b)
• und 5 bis 75 Gew.% eines oder mehrerer Stoffe aus jeweils einer oder mehrerer der Gruppen c), d) und e), wobei
• 0 bis 30 Gew.% c)
• 0 bis 30 Gew.% d) und
• 0 bis 3 Gew.% e) enthalten sind,
• und vorzugsweise
• 20 bis 50 Gew.% a)
• 30 bis 70 Gew.% b)
• und 10 bis 50 Gew.% eines oder mehrerer Stoffe aus jeweils einer oder mehrerer der Gruppen c), d) und e), wobei
• 0 bis 30 Gew.% c)
• 0 bis 30 Gew.% d) und
• 0 bis 3 Gew.% e) enthalten sind.

The mordant has a composition containing

• 20 to 80% by weight a)
• 1 to 80% by weight b)
• and 0 to 79% by weight of one or more substances from one or more of groups c), d) and e), 0 to 35% by weight c)
• 0 to 50 wt.% D) and
• 0 to 5 wt.% E) are included.
• The quantities are expediently given
• ) 20 to 65% by weight a)
• 5 to 75% by weight b)
• and 5 to 75% by weight of one or more substances from one or more of groups c), d) and e), where
• 0 to 30% by weight c)
• 0 to 30 wt.% D) and
• 0 to 3% by weight e) are contained,
• and preferably
• 20 to 50% by weight a)
• 30 to 70% by weight b)
• and 10 to 50% by weight of one or more substances from one or more of groups c), d) and e), where
• 0 to 30% by weight c)
• 0 to 30 wt.% D) and
• 0 to 3 wt.% E) are included.

The composition of the agents can also be selected according to the preferred intended effect.

• 1 bis 50 Gew.% b)
• und 0 bis 49 Gew.%, vorzugsweise 5 bis 49 Gew.% eines oder mehrerer Stoffe aus jeweils einer oder mehrerer der Gruppen
• c), d) und e), wobei
• 0 bis 35 Gew.% c)
• 0 bis 49 Gew.% d) und
• 0 bis 5 Gew.% e) enthalten sind.

If an agent is to be used which, in addition to its lubricating and antioxidative properties, preferably has pickling properties, the composition can contain: 50 to 80% by weight a)

• 1 to 50% by weight b)
• and 0 to 49% by weight, preferably 5 to 49% by weight, of one or more substances from one or more of the groups in each case
• c), d) and e), whereby
• 0 to 35% by weight c)
• 0 to 49% by weight d) and
• 0 to 5 wt.% E) are included.

A particularly suitable agent with outstanding lubricating properties in addition to its action as a mordant and antioxidant can have a composition comprising 20 to 50% by weight of a)

• c), d) und e), wobei
• 0 bis 30 Gew.% c)
• 0 bis 30 Gew.% d) und
• 0 bis 5 Gew.% e) enthalten sind.

50 to 80% by weight b) and 0 to 30% by weight, preferably 5 to 30% by weight, of one or more substances from one or more of the groups in each case

• c), d) and e), whereby
• 0 to 30% by weight c)
• 0 to 30 wt.% D) and
• 0 to 5 wt.% E) are included.

• 20 bis 80 Gew.% a)
• 1 bis 20 Gew.% b)
• und 10 bis 79 Gew.% eines oder mehrerer Stoffe aus jeweils einer oder mehrerer der Gruppen c), d) und e), wobei
• 10 bis 35 Gew.% c)
• 0 bis 50 Gew.% d) und
• 0 bis 5 Gew.% e) enthalten sind.

Furthermore, it is possible to prefer antioxidative properties, while the staining and lubricating properties are fully retained. The composition of the agent can then contain:

• 20 to 80% by weight a)
• 1 to 20% by weight b)
• and 10 to 79% by weight of one or more substances from one or more of groups c), d) and e), where
• 10 to 35% by weight c)
• 0 to 50 wt.% D) and
• 0 to 5 wt.% E) are included.

• 20 bis 22 Gew.% a) in Form von Natriummetaborat und
• 78 bis 80 Gew.% b) in Form von 3 bis 5 Gew.% Graphit und
• 74 bis 76 Gew.% Natriumtripolyphosphat.

A preferred agent contains

• 20 to 22 wt.% A) in the form of sodium metaborate and
• 78 to 80 wt.% B) in the form of 3 to 5 wt.% Graphite and
• 74 to 76% by weight sodium tripolyphosphate.

Generally, the mordant in powder form, said powder having an average grain size of 50 to 1000 _M i-krometer, or mm as a granulate having an average grain size of 0.5 to 4, applied. Depending on the starting materials, this is achieved by intensive grinding and / or mixing of the individual components.

However, the constituents can, for example, also be dissolved or suspended and brought into the use form by spray drying or granulation.

It is also possible to melt the components of the descaling agent, to cool them and to grind the product obtained into powder.

The mordant according to the invention can also be in paste form, as a solution. Suspension and dispersion or be used as Schme _e.

In order to produce a paste or, depending on the solubility, a solution, suspension or dispersion, solvents or dispersing agents, thickeners, stabilizers, etc. must be used in a manner known per se.

The pickling agent can accordingly be processed into a suspension, for example with the aid of suspension aids and water, and sprayed onto or into the hot workpiece immediately before a rolling process.

The agent according to the invention is used for pickling, lubricating and as an antioxidant in the non-cutting hot forming of iron and steel.

For example, it can be used to treat sheet metal before rolling or profile rolling, blocks before extrusion, loops in plug rolling mills, or pipes in upsetting presses.

Other possible uses are in the treatment of the surface to be machined on workpieces in shock banks, Assel, Konti or pilgrim streets, multiple pipe mill systems, etc.

) As a rule, the agent according to the invention is sprayed in dry powder or granulate form, for example onto a sheet to be rolled or sprayed into a pipe to be rolled, in such a way that the entire area covered by the tool, for example the rollers or the mandrel comes into contact, is covered with a uniform layer. Thereby loading

Depending on the processing status, the workpieces are in the range of a treatment temperature of 600 to 1300 ° C. or are already in the range of their rolling temperature of 1000 to 1300 ° C. while the agent according to the invention is being used. ) Immediately after the workpieces have been treated with the agent according to the invention, the shaping process is initiated; cooling in the meantime is neither provided nor necessary.

example 1

A mixture of 50% by weight Na ₂ B ₄ O ₇ . 10H ₂ O and 15% by weight Na ₂ -B ₄ O ₇ as pickling components, 30% by weight of a sodium stearate as layering agent and antioxidant and 5% by weight of a highly crystalline, artificial graphite as solid lubricant were used as powder with a grain size of no more than 200 micrometers worked up in a mixer to a homogeneous mixture of pickling agent and applied in a plug rolling mill in the processing of a scale containing a lot of scale.

Example 2

A pickling agent with emphasized lubricating properties was produced from 70% by weight Na ₅ ^p ₃ 0 ₁₀ and 4% by weight graphite as a lubricating component and 26% by weight Na ₂ B ₂ O ₄ . BH ₂ 0 (sodium metaborate) as a active ingredient by homogeneous mixing, the mixture obtained having an average grain size of 100 micrometers. This fine-particle powder was sprayed into a cavity directly in a contour line before the mandrel rod was inserted, the pickling taking place at the rolling temperature and the proportions of Na ₅ P ₃ O ₁₀ and the graphite during the rolling of the lubrication between the mandrel and the resulting tube made sure.

Example 3

A mixture of 50% by weight of water glass (22% Na ₂ O) and 20 wt% of sodium meta borate (Na ₂ B ₄ O ₁₀ 10H ₂ O.), 5% by weight of graphite and 23 weight% of a mixture of sodium stearate and.... - palmitate led to a mordant with pronounced antioxidant properties. This was made clear by the relatively high proportion by weight of a mixture of sodium stearate and palmitate.

Claims (12)

1. Means for pickling, for lubrication and as an antioxidant for workpieces made of iron and steel in non-cutting hot forming, containing 20 to 80% by weight a) one or more compounds from the series for dressing active compounds Na ₂ B ₄ O ₇ . 10H ₂ O; Na ₂ B ₄ O ₇ . 5H ₂ O; ^Na ₂ B ₄ 0 ₇ anhydrous; Sodium metaborate, NaBO ₂ . 4H ₂ 0; Boric acid, ^H ₃ ^B0 ₃ ; Boric anhydride, ^B ₂ ⁰ ₃ ; soluble sodium silicate with an SiO ₂ / Na ₂ O ratio of 2.5 to 3.3 and Sodium metasilicate, anhydride or with 5 and 9 water of crystallization; 1 to 80% by weight b) one or more dry lubricants from the series of graphite; Calcium fluoride; Cryolite, Na ₃ Al F ₆ ; Antimony oxide, Sb ₂ O ₃ ; Molybdenum disulfide, MoS ₂ ; Boron nitride, BN; one of the phosphates in the series Trisodium phosphate, hydrated or not hydrated tripotassium phosphate, hydrated or not hydrated sodium metaphosphates (NaPO ₃ ) ₃ and ( ^NaP0 ₃ ) ₄ ; Potassium metaphosphate (KPO ₃ ) ₃ and (KPO ₃ ) ₄ ; Polymetaphosphate (NaPO ₃ ) ₄ . H ₂ O; Sodium tripolyphosphate Na ₅ P ₃ O ₁₀ , hydrated or not hydrated, Sodium polyphosphate (Na ₅ P ₃ O ₁₀ ) _2-8 and Zinc phosphate (PO ₄ ) ₂ Zn ₃ ; and 0 to 79% by weight of one or more substances from one or more of groups c), d) and e), which contain 0 to 35% by weight c) one or more additives from the series which influence the layer formation in the rock and act as an antioxidant Coke, powdery carbon, Powdered cellulose, sawdust, starch and their derivatives, Paraffins, waxes Fatty acids and / or salts thereof, Rosin and its derivatives, synthetic resins based on hydrocarbons with 5 to 10C atoms, and Indene-coumarone resins; 0 to 50% by weight d) one or more substances from the magnesium chloride MgCl ₂ series controlling the physical properties of the agent. 6H ₂ 0, Sodium chloride, Potassium chloride, Calcium chloride, Sodium sulfate, Sodium acetate, Potassium acetate and Clays;
and 0 to 5% by weight e) one or more substances on the reduction of the oxides and separating substance from the series Ammonium chloride NH ₄ Cl, Urea CO (NH ₂ ) ₂ , Ammonium carbonate (NH ₄ ) ₂ CO ₃ , Urea-formaldehyde resin, Sodium carbonate Na ₂ C ^o ₃ contain. 2. Composition according to claim 1, containing 20 to 80 wt.% A), 1 to 75 wt.% B) and 5 to 79 wt.% Of one or more substances each from one or more of groups c), d) and e ), c) in amounts of 0 to 35% by weight, d) in amounts of 0 to 50% by weight and e) in amounts of 0 to 5% by weight. 3. Composition according to patent claims 1 and 2, containing 20 to 65% by weight a), 5 to 75% by weight b) and 5 to 75% by weight of one or more substances from one or more of groups c), d) and e), wherein c) is contained in amounts of 0 to 30% by weight, d) in amounts of 0 to 30% by weight and e) in amounts of 0 to 3% by weight. 4. Composition according to patent claims 1 to 3, containing 20 to 50% by weight a), 30 to 70% by weight b) and 10 to 50% by weight of one or more substances from one or more of groups c), d) and e), wherein c) is contained in amounts of 0 to 30% by weight, d) in amounts of 0 to 30% by weight and e) in amounts of 0 to 3% by weight. 5. Composition according to claim 1 for lubrication, as an antioxidant and preferably for pickling workpieces made of iron and steel in the non-cutting hot forming, containing 50 to 80% by weight a), 1 to 50% by weight b) and 0 to 49% by weight, preferably 5 to 49% by weight of one or several substances from one or more of groups c), d) and e), where c) in amounts from 0 to 35% by weight, d) in amounts from 0 to 49% by weight and e) in amounts from 0 to 5% by weight is included. 6. Composition according to claim 1 for pickling, as an antioxidant and preferably for the lubrication of workpieces made of iron and steel in the non-cutting hot forming, containing ' 20 to 50% by weight a) 50 to 80% by weight b) and 0 to 30% by weight, preferably 5 to 30% by weight, of one or more substances from one or more of groups c), d) and e), where c) in amounts of 0 to 30% by weight, i.e. ) in amounts of 0 to 30% by weight and e) in amounts of 0 to 5% by weight. 7. Composition according to claims 1 and 6, containing 20 to 22 wt.% A) in the form of sodium metaborate and
78 to 80% by weight b) in the form of 3 to 5% by weight graphite and 74 to 76% by weight sodium tripolyphosphate. 8. Composition according to claim 1 for pickling, for lubrication and preferably as an antioxidant of workpieces made of iron and steel in the non-cutting hot forming, containing 20 to 80% by weight a) 1 to 20% by weight b) and 10 to 79% by weight of one or more substances from one or more of groups c), d) and e), where c) in amounts of 10 to 35% by weight, d) in amounts of 0 to 50% by weight. % and e) is contained in amounts of 0 to 5% by weight. 9. Agent according to claims 1 to 8 for pickling, for lubrication and as an antioxidant at workpiece temperatures of 600: to 1300 ° C, preferably 1000 to 1300 ° C. 10. Use of the agent according to claims 1 to 9 for pickling, for lubrication and as an antioxidant for workpieces made of iron and steel in non-cutting hot forming, preferably for pickling, for lubrication and as an antioxidant for steel blanks at rolling temperature. 11. Use of the agent according to patent claims 1 to 10 for pickling, for lubrication and as an antioxidant for workpieces made of iron and steel in non-cutting hot forming, preferably for pickling, for lubrication and as an antioxidant for steel blanks at rolling temperature in plug rolling mills (plug mills). 12. Use of the agent according to claims 1 to 11 for pickling, for lubrication and as an antioxidant at workpiece temperatures of 600 to 1300 ° C, preferably at 1000 to 1300 ° C.