Fengfan Chemical Derusting Rust Removing Agent 988 For Metal Pre Treatments Use

Product Overview

Fengfan Chemical Derusting Rust Removing Agent 988 is a hydrochloric acid pickling additive for steel that has to be clean before it can be plated. It works on two fronts at once: it accelerates the breakdown of rust and oxide, and it holds the base metal back so the acid slows down the moment the corrosion is gone. That combination is what separates it from a plain acid dip — the tank still strips scale, but it stops treating clean steel as though it were rust. Among the metal finishing chemicals on a pretreatment line, this is the one whose behaviour decides whether the plating chemicals that follow produce a coating that actually holds.

The additive was formulated for the steel substrates where a pitted or over-etched surface shows up immediately in the finished plate. It runs at ambient shop temperature without heating, and it goes into the hydrochloric acid you already have rather than needing a line rebuilt around it. For an industrial metal plating operation, that is what makes it practical to prove on a single tank before rolling it out across the shop.

Performance Advantages

• Selective inhibition, not just faster acid. The inhibitor adsorbs onto clean steel once the oxide has lifted, forming a temporary molecular shield that halts the acid attack while the acid keeps dissolving whatever scale remains. Dimensions stay inside tolerance and delicate threads and fine features survive the dip, which is exactly where derusting usually turns into scrap.
• Rust and black oxide come off faster. Surfactants lower the surface tension of the bath so the acid reaches into micropores, weld seams and pits instead of sitting on top of the corrosion. Loads that used to need a second pass through the tank generally clear in one immersion.
• A noticeably quieter tank. Acid-fog inhibition is strong here — the bath does not throw off the choking mist a plain hydrochloric dip produces, and that reduction in fume protects overhead cranes, extraction ductwork and nearby electronics from acid attack. The same suppression means less acid is lost to evaporation over a working week.
• Longer acid life, lighter effluent. Because the reaction with the base metal is suppressed, the acid is spent dissolving oxide rather than dissolving steel. Hydrochloric acid consumption comes down and the load on wastewater treatment comes down with it — two cost lines that move together in any metal plating process.
• A degreasing assist built into the dip. Emulsifying surfactants undercut and displace light oil films and shop soil that survived the alkaline stage, and the improved wettability leaves a water-break-free surface. That is the condition the plating chemicals downstream need in order to spread evenly instead of beading, and it also stops removed soil from settling back onto the part.
• Nothing carried into the next bath. The additive leaves no side effects on the acid balance or on the coating that follows, so zinc, copper or nickel deposits go down clean and the oxide haze that clouds a plate is dealt with at the source. On a line running several electroplating chemicals in sequence, one predictable pretreatment step is what keeps everything after it predictable.

Bath & Operating Conditions

Use Scenarios

• Restoring oxidised automotive components. A refurbishment shop plating vintage parts runs into the same wall every time: a standard acid dip strips the rust, then keeps going into the threads, cast markings and close-tolerance faces that make the part fit. Running the tank with this additive takes the thick corrosion off and leaves a clean metallic grey surface with the detail still there, so parts that would otherwise be scrapped go back into service.
• High-tensile fastener production. In a plant making Grade 8.8 bolts, delayed fractures that only appear after the process of electroplating is finished are usually traced back to uncontrolled pickling. Selective inhibition cuts hydrogen evolution at the metal surface during the dip, so the bolts come through with their tensile strength intact and late failures on the line drop away.
• Automatic zinc plating lines. On high-volume automatic lines the recurring problem is drag-out — acid carried out on the work and into the rinse tanks and flux baths. The lower surface tension of the bath improves drainage and cuts drag-out by 20%, so rinse water stays cleaner for longer and the waste treatment plant carries a smaller load. For metal plating services running three shifts, that shows up directly in operating cost.
• Wire, cold strip and tube production. These are the substrates this additive was built around, including continuous lines where the work runs through the acid without stopping. The bath holds its strength through a long shift, which matters more on a continuous line than on rack work.
• Mixed loads and variable incoming condition. Job shops rarely see one rust level in a week. The same charge handles light flash rust and heavy heat-treat scale, with the immersion adjusted inside the working window rather than a second tank mixed — useful for an industrial metal plating shop where floor space is tight and every tank has to earn its place.

Bath Control & Handling

Charging the tank follows ordinary pickling discipline: water first, then the hydrochloric acid, then the additive, stirred through before the first load goes in. Watch the Baume reading rather than the calendar — it falls as the acid is consumed by oxide and it is the fastest signal that the bath is drifting lean. Top up acid and additive together; a tank running on acid alone is exactly the condition the inhibitor exists to prevent, and it is where good metal finishing chemicals get blamed for a bad result.

The bath does not need heating to work — an ambient shop temperature is enough — but a warm tank reacts faster than a cold one, so shorten the dip when the solution is hot and the scale is light. Sludge accumulates as scale dissolves, so draw it off or filter it; solids picked up on the way out of the tank are one of the quiet causes of a rough or poorly bonded deposit later in the metal plating process.

Load the tank so solution can move around the parts. Nested or stacked components trap air and pickle unevenly, and barrel work needs the same freedom to tumble. Move the load to the rinse as soon as the scale is gone rather than letting it stand. Before a new tank is charged, ask your sales contact for the current SDS and for dosing guidance matched to your bath — the routine a metal plating services line settles into is easier to hold when it is written down once and checked each shift.

Pretreatment Sequence

1. Degrease. Alkaline cleaning comes first, by immersion or electrolytically, to strip drawing oils, stamping lubricants and polishing residues. Fengfan's 896 covers steel, iron and non-ferrous work; 898A is the phosphorus-free grade for steel parts and 898B is formulated for aluminium and its alloys.
2. Derust. The acid tank, running with this additive, removes rust, black oxide and heat-treat scale. This is the step that decides how the rest of the metal plating process will perform, because nothing downstream bonds to oxide that was left behind.
3. Rinse. Running cool water, then a second rinse, so no acid is carried into activation. The lowered surface tension from the additive helps the film drain off the part instead of hanging on it.
4. Activate. A short dilute hydrochloric acid dip removes any film that formed during rinsing and leaves the surface chemically receptive to the deposit.
5. Plate. Into the zinc, copper, nickel or alloy bath, where the electroplating chemicals take over and the quality of the derusted surface shows up as brightness, adhesion and coverage.
6. Source the rest of the line. The steps either side of derusting are covered by the same range — FP-93 phosphating agent, SZ-30B and ZN-500 zinc brighteners, FI-970 bright acid copper, Nickel Purify P3, EB 204A-204B tin-salt colouring, 149-L and 149-T anodising sealants, FF-116 chrome mist inhibitor and FF-4219 nano-protection for wood, stone and concrete — all formulated by a company that has worked in surface finishing since 1984.

Packing, Payment & Delivery

Acid Mist & Shop Air

• Run correctly, the acid fume problem in the shop gets better, not worse. The 988 additive holds a foam blanket over the hydrochloric acid bath and inhibits the acid's attack on clean steel, so less hydrogen is generated at the surface and less mist rises into the working area.
• The effect operators notice first is at the tank edge: less choking, less eye irritation and a weaker acid smell through the shift. That is the difference between a pickling line people can work around comfortably and one that sends them reaching for a respirator every time a load goes in.
• Equipment corrosion follows the same path. Acid mist settles on crane rails, overhead steelwork, fan blades, ductwork and electrical cabinets, and over months it eats into exactly the parts that are expensive to repair or replace. Keeping the mist in the tank protects that equipment and reduces the frequency of cleaning and repainting in the roof space.
• The extraction system carries a lighter load. Because the foam blanket traps mist before it reaches the duct, the scrubber or extraction fan sees less acid, ductwork stays cleaner for longer and the maintenance interval on the fume system extends. That is a direct saving on extraction upkeep, not just a comfort improvement.
• Fume conditions get worse when the bath is hot, the acid strength is high, the scale load is heavy or the work is moved vigorously. Stay inside the 5–50 °C window, keep the bath at 10–17 °Be', maintain the foam cover and check the extraction before a heavy shift. If the blanket breaks down or the tank runs unusually hot, shorten the immersion and bring the bath back into range.
• The additive lowers the mist load; it does not replace ventilation or PPE. Keep the extraction hood running, follow your acid-handling procedure and wear the protection your risk assessment calls for. Treat the foam blanket as the first control at the tank and the extraction system as the backup, then watch both.
• On an industrial metal plating line running several metal finishing chemicals in sequence, the benefit carries downstream. Less mist means less acid carry-over into the rinse, so rinse water and wastewater treatment carry a lighter load, acid consumption comes down and the shop floor stays more comfortable for the people who load and unload the work.

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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