Two Alloys on the Job Card. One Shift to Get It Right.

Monday morning. Casting floor, Rajkot.

The production coordinator picks up the first two job cards from the stack. Card one: stone-in-place tree, 18 KT yellow, twelve pieces with melee settings. Card two: plain casting, same 18 KT yellow, thirty bangles, no stones.

Two different alloys. Two different temperature protocols. Two different cooling schedules.

By the time the shift ends, there’s a good chance at least one of these will go wrong. Not because anyone is careless. Because the system itself has two sets of rules for what should be a single material.

And that’s before we talk about colour.

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‍The Hidden Cost of Running Two Yellow Gold Alloys

Here’s what we hear from casting units across Mumbai, Surat, Rajkot, and Coimbatore: the alloy decision for yellow gold gets made once often years ago and never revisited. Stone-in-place work gets one alloy. Plain casting gets another. Sometimes there’s a third for age-hardenable pieces.

Nobody questions it because it’s always been that way. But the costs accumulate quietly:

Alloy mix-ups: Wrong alloy in the crucible. You only discover it when pieces come out off-colour or brittle. The tree is scrap. At today’s gold prices, that’s not a minor write-off.

Soft prongs, loose stones: Your stone-in-place alloy casts fine but won’t hold up under daily wear. The retailer doesn’t call to discuss metallurgy. They call your competitor.

Colour drift across batches: Two alloys, two slightly different shades of ‘18 KT yellow.’ The buyer notices when pieces from different production lots sit together in the same display case. Shipments get held. QC hours go up.

Changeover waste: Every time the crucible switches alloys, there’s a transition melt. Waste metal. Lost time. Do hazaar pieces ke order mein yeh chota lagta hai. But multiply it across a month and it adds up.

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‍One Alloy. Every Casting Method. One Colour.

SCA4 from Legor Group is a copper–silver–zinc master alloy built for exactly this consolidation. It covers stone-in-place, closed-system, open-system, and plain casting all from a single product.

The melting range is just 20°C (solidus 860°C, liquidus 880°C). That’s narrow enough to give your casting head a forgiving window. Fewer short-fills. Fewer gas traps. More predictable flow into fine detail regardless of whether there are stones on the tree or not.

The colour is a consistent pinkish-yellow. Not warm, not greenish balanced. And because the composition is fixed and lab-documented (CIE L*a*b* coordinates provided per batch), what you cast today will match what you cast next month.

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What Changes on Your Shopfloor

One alloy, all job cards: The coordinator picks up the stack and runs the same material all shift. No switching, no confusion, no transition melts.

260 HV when you need it: As-cast hardness is 150 HV already solid. But for prong-heavy designs or stone-in-place work, a single-step age hardening (250°C, 90 minutes) takes it to 260 HV. Stronger settings. Fewer returns.

Batch-consistent colour: Every lot delivers the same pinkish-yellow shade. Your buyers get what they ordered. Your QC team stops spending hours on colour-matching.

Medium deoxidation built in: Cleaner castings out of the flask. Less aggressive pickling. Better surface finish heading into polishing.

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‍What This Won’t Fix

We should be upfront about this, because no alloy solves everything:

SCA4 won’t rescue a bad burnout schedule. It won’t compensate for overheated melts or worn-out crucibles. If your investment material is inconsistent, your surface finish will still suffer regardless of which alloy you pour.

Age hardening is optional, not automatic. You need a furnace that holds 250°C accurately for 90 minutes. Without that, you’re working with the 150 HV as-cast hardness, which is good but not exceptional.

And SCA4 covers 18–22 KT. If you’re primarily doing 14 KT or below, this isn’t the product for you.

Par agar aapka casting process solid hai and the complexity is coming from juggling multiple alloys, multiple protocols, multiple colour standards yeh woh variable hai jo consolidate ho sakta hai.

Worth Simplifying?

Run SCA4 against your current alloy on your own trees. Compare fill quality, colour match, and post-hardening performance side by side.

We’ll share Legor’s recommended casting parameters for your specific piece thickness flask and metal temperatures documented by weight range. No guesswork. ‍

Reach out: help@preciousalloys.com  |  +91-22 6101 4444