Fengfan Fast Chromo Phosphating Agent Room Temperature Metal Pretreatment Chemicals FP-93

Product Overview

FP-93 is a chromo-phosphating concentrate that builds a conversion film on steel and iron at ambient shop temperature. Mixed at 50 ml/L in water, it turns a cleaned steel surface into a fine crystalline phosphate-chromate layer that paint, powder and adhesive grip far more aggressively than they grip bare metal. Nothing about the tank is complicated: one concentrate, a little sodium hydroxide to set the balance, and a rinse station either side. That simplicity is why industrial metal plating shops, powder coaters and fabrication plants run it as a standing paint base.

In a coating line the tank sits after degreasing and derusting and immediately before the first paint or powder stage — the last wet station in the metal plating process before the surface is sealed. It replaces a hot phosphating bath held above 60 °C and cycled for 15–20 minutes: this one runs cold, finishes in a fraction of that time, and needs no heating infrastructure, no steam line and no warm-up at shift change.

Shops that also run electroplating metal parts use the same stage as an inter-process barrier. A phosphated bracket can sit overnight in a humid workshop, or wait in a stillage for the next operation, without flash rust forming on the surface that has just been prepared.

Key Features

• Room-temperature activation. The working bath runs between 20 °C and 40 °C, so there is no heating coil, no steam line and no warm-up wait at the start of a shift; a plant that used to hold a hot phosphating tank can shut that loop down.
• Fast, controllable film. A functional conversion coating forms in 3–7 minutes at room temperature, and heavier films can be taken to about 10 minutes where the job needs more weight.
• A real anchor for paint. The crystalline phosphate-chromate layer gives the coating a micro-rough profile to key into, which is what turns adhesion from a hope into something you can measure on cross-hatch and impact tests.
• Corrosion resistance built into the film. The finished layer is typically iridescent, golden through to blue, and the chromium in it keeps passivating the surface after the part leaves the tank, which is what holds rust back during storage and between operations.
• Thermal and impact stability. The film keeps its adhesion when the coated part is baked, formed or knocked, so components handled roughly between coating and assembly do not arrive with chipped edges.
• Far less sludge. Sediment build-up is much lower than with zinc or manganese high-temperature phosphating, so tank cleaning and sludge disposal take a fraction of the downtime they used to.
• Simple titration control. A total acidity of 14–18 and a free acid of 1–2.5 tell you everything about bath strength; there is no multi-component dosing schedule to juggle, and the bath tolerates minor contamination without drifting in colour or film weight.
• A bath operators do not mind working over. The working solution is odourless and clear, with a specific gravity of 1.08, and it is non-inflammable, non-explosive and non-volatile, so there is no vapour to extract and no solvent smell on the shop floor.
• The same technical team as your other chemistry. The concentrate comes from the group that formulates our electroplating chemicals, so bath make-up figures and titration practice can follow the methods your laboratory already uses.
• One supplier for a mixed plant. Where a shop runs metal electroplating on one side of the plant and a paint line on the other, both sides can be specified, documented and replenished on one schedule.
• Coexists with a plating line. Plants that also handle electroplating metal work keep the phosphating tank on its own rinse circuit, so the two processes share a building without sharing a bath.

Specifications

Process Flow & Bath Control

1. Clean the part first. Degrease and derust before anything else; in a metal plating process this tank should only ever see a water-break-free surface, because oil, scale and rust stop the film forming and leave a patchy, mottled result.
2. Rinse off the cleaner. Carry-over drags alkali into an acid bath and shifts the free acid, so rinse thoroughly and let the part drain before it goes in.
3. Make up the bath. Add 50 ml/L of the concentrate and 0–1 g/L sodium hydroxide to the water, stir to uniformity, then bring to final volume.
4. Check the acid points before the first job. Total acidity should read 14–18 and free acid 1–2.5 at a working pH of 2–3; if either is out of range the film will be thin, slow or uneven.
5. Immerse for 3–7 minutes. Hold the bath between 20 °C and 40 °C, rack or basket the parts so solution reaches every face, and give blind holes and overlaps a moment of agitation.
6. Rinse and dry. A clean rinse stops residual acid drying on the surface, and drying completes the film; parts can go straight to paint or into short-term storage.
7. Watch the film, not the clock. Colour and coverage tell you more than time does — a thin, patchy film usually means a weak bath or a dirty part, not that the immersion was too short.
8. Replenish on titration. Top up with concentrate to bring total acidity back into range; because the bath is a single-component system, it needs fewer additions and less analysis than most plating chemicals in the plant.

Use Scenarios

• Outdoor electrical enclosures. A plant running steel distribution boxes for outdoor service puts the tank ahead of the powder booth, so every box leaves with a golden conversion layer under the coating; if the finish is later scratched, the film under the paint is what stops rust creeping sideways from the damage. Because the line starts at ambient temperature, there is no waiting for tanks to heat at shift change.
• Automotive parts refurbishment. A workshop reconditioning brackets and suspension arms after abrasive blasting dips them to seal the freshly blasted steel before it can flash rust in a humid shop, then paints over a surface that has had no time to oxidise.
• Appliance panels. A process engineer replacing an inconsistent iron phosphating stage — at an appliance plant, or at metal plating services supplying one — uses this bath to give steel sheet a uniform surface energy, which is what makes powder flow evenly and hold through forming and baking.
• General machinery housings and fabricated steel. Weldments, guard frames and machine covers are usually too large for a heated line and too visible to paint over a patchy base; a dip or a spray at ambient temperature handles both problems at once.
• Job shops with mixed batches. A small dip tank, one concentrate and a titration kit make a complete pretreatment station, which is what most industrial metal plating work needs when batch sizes change weekly and a heated line would never pay for itself.
• Where pretreatment and topcoat are bought as a pair. Buyers comparing paint chemicals suppliers usually want one base chemistry across the line, so the concentrate is specified against the powder or liquid coating already in use rather than chosen on its own.

About Fengfan

Fengfan has been formulating surface-finishing chemistry since 1984. Wuhan Fengfan Electrochemical Technology, the parent company, is listed on China's National SME share transfer system under stock code 430221, and Fengfan International Trade is its wholly owned export arm. The business grew out of electroplating chemicals — additives, intermediates and brighteners — and the laboratory that develops them also formulates the pretreatment range this concentrate belongs to.

Production sits at the Fengfan Tech Park in Wuhan's Dongxihu District: about 67 acres, roughly 7,000 m² of floor space and an annual capacity of 3,000–5,000 t of surface treatment additives, run under 6S scene management and a classified logistics system, with a pilot laboratory available for process trials. Lines that run metal electroplating and painting side by side benefit most, because the same discipline that keeps a plating bath reproducible is applied to the pretreatment tank — acid points and film colour checked batch by batch rather than assumed.

Export buyers usually reach the range through Fengfan International Trade, which is how paint chemicals suppliers, coating lines and job shops outside China buy pretreatment, plating and post-treatment chemistry as one documented package.

Ordering & Delivery

1. Choose the pack size. The concentrate is supplied as 10 kg/box; 25 kg or 50 kg/bag; 20 kg/25 kg/30 kg/200 kg/drum; 1,000 kg/IBC drum.
2. Confirm the minimum order quantity. It varies by chemical and is confirmed with our sales team per order — whether you run a captive line or provide metal plating services to third parties, tell them the bath volume and they will work back from it.
3. Plan the production time. Lead time is 2 weeks; if the order also carries plating chemicals for other stages, ask for one delivery schedule so the drums arrive together.
4. Arrange payment. Payment is 100% T/T in advance.
5. Agree the shipping terms. Shipping runs per the terms agreed in the current contract.
6. File the delivery document. After delivery an inspection certificate is issued stating the batch number and warranty period — keep it against the drum, especially where the same store room also supplies electroplating metal finishing elsewhere in the plant.

Topcoat Compatibility

• Powder coatings. Epoxy, acrylic and polyester powders all key to the film. Epoxy systems are the usual choice where corrosion and chemical resistance lead the specification — electrical cabinets, chassis parts, machinery housings; polyester where exterior colour and gloss retention matter more; acrylic where appearance is the priority. The micro-rough phosphate-chromate profile is what the powder mechanically locks into during cure.
• Liquid paints and primers. Solvent-borne and water-borne primers and topcoats behave the same way over the dry film: good wet-out, fewer pinholes, and a scribe line that resists under-film creep. Where a two-coat system is specified, put the film under the primer, not between coats.
• Protective oils. Where parts are stored or shipped before painting, a light protective oil over the dry film holds rust back for days without needing to be stripped before the coating stage; check with your oil supplier that it is compatible with the paint system you run.
• Film weight matched to the coating. A 3–7 minute dip gives the normal production film. High-build powder and heavy epoxy systems generally want a slightly heavier film, so take the immersion toward 10 minutes and judge colour depth and coverage before you fix the cycle.
• Bake and forming. The film is thermally stable and impact resistant, so it comes through a powder bake and the handling or forming steps that follow coating; that is what keeps edges from chipping on the assembly line.
• Prove it on your own coating. Run a cross-hatch adhesion test and an impact test on panels coated with the actual powder or paint from your booth, and record salt-spray hours alongside film weight and coating thickness. A salt-spray figure without those three numbers cannot be compared with anyone else's.
• Tell us the coating system before the bath is made up. Substrate, topcoat type, cure schedule and target corrosion hours let us confirm bath concentration and immersion time. Buyers who source pretreatment and topcoat from different paint chemicals suppliers should still have both datasheets on the table at the same time.
• Specialist systems. E-coat, high-solvent vinyl, PVDF and similar finishes sit outside the common range, so trial them on panels before a production bath is made up. Send us the topcoat datasheet with the panel results and we will advise on film weight and rinse quality.

Pretreatment Line Pairing

• Degreasing ahead of the tank. Phosphating only works on a water-break-free surface, so the station before it does the heavy lifting. Our 896 degreasing agent covers steel, iron, zinc-aluminium and other non-ferrous metals in chemical or electrolytic mode, with 1–10 minute cycles at up to 75 °C, for batch or continuous work.
• Phosphorus-free cleaning for steel. Where the line has to run without phosphorus, 898A is the steel-parts cleaner: a white powder used at 50–80 g/L and 15–50 °C in roughly five-minute cycles. It is the pairing most shops choose for cold-rolled sheet and pressed components.
• Derusting before phosphating. 988 rust remover works in a hydrochloric acid bath at 200–600 ml/L with 30–50 ml/L of additive, 5–50 °C, 1–30 minutes. It keeps the true metal colour, suppresses acid fog and holds over-pickling back, which matters on thin sheet and wire.
• Rinse discipline between stages. Carry-over is the usual reason a bath will not hold its acid points: rinse after cleaning and rinse again after derusting, so cleaner residue and dissolved iron do not land in the phosphating tank.
• Rinse and dry after the film. Two clean rinses — the second preferably deionised where the topcoat specification is tight — then dry-off before the paint or powder stage. Residual acid left to dry on the surface is what later shows up as blistering or weak adhesion.
• Tank and handling. A dip tank or spray chamber with a suitable liner, plastic or stainless rinse stations, and the same racks or baskets already used on the line. There is no heating circuit to install or maintain.
• Control instruments. A burette set for total and free acid, a pH meter and a specific gravity cup cover the whole bath; total acidity of 14–18 and free acid of 1–2.5 are the only routine analysis needed.
• One documentation package. Pretreatment, plating and post-treatment chemistry can be ordered and documented together, so a plant running industrial metal plating on one side and coating on the other keeps one set of batch certificates, safety data sheets on request, and one technical contact for both.

Technical Support & Model Matching

Choosing the right match is where most sourcing decisions stall. As a trading supplier, we keep one point of contact from first enquiry to after-sales: tell us what you are making and the conditions you work under, and we shortlist the closest matches from our supplier network, compare specifications and arrange samples before you commit to a bulk order. If something does not behave as expected, we work with the supplying partner on the cause and a practical fix, and stay with the case until it is settled. Email, WeChat or WhatsApp enquiries get a reply within 24 hours.

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