How to Challenge a Casting Price Increase With Data

The letter arrives - usually in Q4, sometimes in January, occasionally in the middle of a delivery crisis when you are least positioned to push back. "Due to increased raw material and energy costs, we are adjusting prices by X% effective [date]." Sometimes there is a chart. Sometimes there is nothing but the number.

Most procurement teams respond in one of two ways: they accept, or they negotiate by feel - asking for a lower percentage without any specific basis. Neither is a strong position. The supplier has done their homework. You need to do yours.

Here is a structured approach to responding to casting price increase requests using publicly available market data combined with a should-cost model.

Step 1: Decompose the claimed increase by cost driver

Before you respond to anything, you need to know what the increase is actually claiming. A 12% increase is not one thing - it is a blended number that could be made up of several different cost drivers moving by different amounts.

Ask the supplier - in writing, before any negotiation conversation - to provide a cost breakdown of the increase. Specifically: what percentage of the increase relates to material cost, what percentage to energy, and what percentage to labour or overhead. Most will resist this, but the request itself signals that you are not operating on instinct.

Even if they do not provide the breakdown, you can estimate it yourself. A typical iron casting cost structure is roughly: 60% material, 15% moulding/overhead, 12% melt/energy, 8% finishing, 5% margin. If those proportions hold and the supplier claims energy drove the increase, a 12% total increase implies energy costs rose by 100% - which you can verify against public data.

Step 2: Check material market data for the period

Scrap steel and cast iron prices are published monthly by multiple sources - the European Scrap Price Index, Fastmarkets, and national steel associations all publish data. For the period covered by the price increase claim, pull the average scrap price in the supplier's country and compare it to the price 12 months earlier.

If scrap rose 8% and material is 60% of cost, the material contribution to the total cost increase is 0.60 × 8% = 4.8 percentage points. If the supplier is claiming 12% total, that leaves 7.2 percentage points to be justified by other drivers.

This calculation gives you a defensible counter-position: "Our data shows scrap increased by approximately 8% in your market over the relevant period. On a part where material represents 60% of cost, this justifies approximately 5% of the claimed increase. We would like to discuss the basis for the remaining 7%."

Step 3: Check energy price data for the period and market

Industrial electricity prices in Europe are published by Eurostat quarterly, with country-level breakdowns. For gas-using foundries (cupola or gas-fired furnaces), gas price indices are published monthly by national energy regulators.

Energy typically represents 10–15% of casting cost. A doubling of electricity prices (which did happen across much of Europe in 2022–2023) would justify a 10–15% total cost increase from energy alone. But you need to check the specific country and the specific period - the variation across markets was significant.

By 2024, energy prices in most European markets had partially retreated. A supplier still citing "energy cost increases" in mid-2024 based on 2022 peak prices is applying an adjustment that the market has partially reversed. This is worth checking.

Step 4: Build your counter-position

With the material and energy data in hand, you can build a structured counter-position document. It does not need to be long - two pages is enough. It should contain:

1. Acknowledgement of the cost pressures the supplier has experienced - specific and factual, not diplomatic.
2. Your calculation of the material cost movement and its contribution to total part cost, with the data source cited.
3. Your calculation of the energy cost movement and its contribution, with the data source cited.
4. The increase you are prepared to accept, based on the data - typically a partial acceptance.
5. A request to discuss the remaining claimed increase, with a specific meeting date proposed.

This approach does three things. First, it gives the supplier a face-saving path - you are not accusing them of bad faith, you are comparing data. Second, it signals that your team has the analytical capability to do this every time, which changes the dynamic for all future increase requests. Third, it often results in the supplier withdrawing or modifying the uncovered portion of the increase without a meeting.

Step 5: Use the should-cost model as a reference floor

The final layer of the challenge is a should-cost benchmark - a model-based calculation of what the part should cost at current market rates, given the part's geometry, material grade, and production parameters.

If your should-cost model shows that at current material and energy prices, the part should cost €4.20/kg, and the supplier's post-increase price would be €5.10/kg, you have a meaningful gap to work with. This is not the same as saying the supplier is wrong - overhead structures, quality investments, and local conditions all affect actual cost. But it gives you a reference point that shifts the conversation from "we think this is too much" to "our model shows current market conditions support a price of approximately X - can you help us understand what drives the gap?"

Very few procurement teams have this capability. Those who do find that supplier relationships actually improve - because the conversation becomes factual rather than adversarial, and suppliers know they are dealing with a counterpart who understands their business.

A note on timing

Price increase requests that arrive during a supply crisis - when you are short of parts, when tooling is only at one supplier, when a production line is at risk - are the hardest to challenge. The supplier knows your leverage is low.

The best time to build this analytical capability is not when you need it. It is six months before you need it - when you have time to run benchmarks on your key parts, understand which suppliers are most competitive at current prices, and identify where you have alternative sourcing options if negotiations fail. Reactive preparation is expensive. Proactive preparation is cheap.