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1.2316 Stainless Mold Steel Dual Identity: Corrosion Resistance With Mold-Grade Strength and Hardness

Common stainless steel can resist rust well, but it becomes too soft to use as molds. Regular mold steel has high hardness, yet it gets rusty when touching water. This is the classic trade-off problem in the plastic mold industry. 1.2316 Stainless Mold Steel perfectly solves this conflict. It contains 16% chromium for reliable rust resistance, and 0.25-0.35% carbon to gain hardness after quenching as martensitic steel. This article explains how it meets both stainless steel and mold steel requirements at the same time.

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1.2316 Stainless Mold Steel
1.2316 Stainless Mold Steel
DIN 1.2316
DIN 1.2316
1.2316 steel turned bar
1.2316 steel turned bar
1.2316 steel milled surface
1.2316 steel milled surface
1.2316 milling service
1.2316 milling service
1.2316 material milled surface
1.2316 material milled surface

Where does the stainless feature of 1.2316 Stainless Mold Steel come from?

A mix of 16-18% Cr, 0.60-1.00% Ni and 0.80-1.30% Mo is the core reason why 1.2316 Stainless Mold Steel resists rust. Cr builds the basic anti-rust film. Ni makes this film more stable and tough. Mo specially stops small rust holes caused by chloride ions. All three metal elements are necessary.
Take 4Cr13 (S136) for comparison. It only has 12-14% Cr, no Ni and no Mo. Its anti-rust ability is one or two levels lower than 1.2316. It works fine in normal wet conditions. But when used for PVC injection molds, HCl gas harms 4Cr13 much more seriously than 1.2316. 1.2316 stainless steel becomes a top choice among anti-corrosion mold steels, all because of this three-part formula of Cr, Ni and Mo.

How does 1.2316 Stainless Mold Steel keep both hardness and easy machining at the same time?

Most people think stainless steel cannot be hard. 304 stainless steel is soft just like aluminum. But 1.2316 Stainless Mold Steel belongs to martensitic steel. It has 0.25 to 0.35 percent carbon. Quenching can create hard martensite structure inside it.

How to get pre-hardened hardness of 28-34 HRC?

First do quenching: heat to 1000-1050°C to turn into austenite, then cool in oil. This step makes hardness reach 50-56 HRC martensite. Next, high temperature temper at 600-650°C. This process lets carbide separate out and lower hardness back to 28-34 HRC. This hardness range is well designed. It is hard enough, so it will not dent easily like soft 304. It is not too hard for cutting either. Standard high speed steel cutting tools can machine it smoothly. 1.2316 tool steel owns mold steel hardness plus stainless steel anti-rust ability. That is its real market position.
 

The Irreplaceable Value of 1.2316 Stainless Mold Steel for High Cleanliness Applications

Food packaging molds must not rust. Anti-rust oil cannot be used, as it will contaminate food. Workers clean the molds with steam every time production stops. Plastic parts for medical devices follow strict hygiene rules. No rust risk is allowed on mold surfaces. Optical lens molds get mirror polishing. Even tiny rust spots will turn finished goods into waste.
 
These three working cases share one same feature. Regular mold steel like P20 and 718 cannot be used at all. They have to be coated with anti-rust oil, and anti-rust oil is strictly banned in these scenarios. 1.2316 plastic mold steel stays rust-free for a long time without anti-rust oil. This is its main advantage in this special market. Its price is higher, but for high cleanliness production, it is not an optional choice, but a necessary material.

Polish Performance of 1.2316 Stainless Mold Steel

1.2316 Stainless Mold Steel has medium to good polish performance. The LF plus VD refining process controls tiny impurities inside the steel. Steel with high purity can be polished down to Ra 0.05 μm or even smoother. Food packaging molds and optical lens molds must reach this smooth standard. Any small scratch on the mold will copy onto finished plastic products.
If you need an ultra-smooth mirror surface with Ra ≤0.02 μm, pick 1.2316 mold steel made with ESR process. ESR cuts sulfur content to ≤0.005% and greatly reduces impurities. It speeds up polishing work a lot. To get the same mirror finish, ESR steel only needs 30 to 40 percent less polishing time than regular 1.2316 steel. Not all molds need ESR material, but mirror molds are worth the extra cost.

FAQ:

Q1: Can 1.2316 Stainless Mold Steel replace S136?

A: It depends on your working conditions. If you need strong corrosion resistance for PVC or food packaging molds, 1.2316 works better than S136. It has 4% more chromium, plus nickel and molybdenum. If you need top mirror polish and there is no strong corrosive plastic, S136 may be a better pick. These two steel grades cannot fully take each other’s place; they match different needs. Choose based on your production needs instead of only comparing prices.

A: Its higher price comes from expensive alloy metals. Chromium, nickel and molybdenum all cost a lot. 1.2316 contains much more alloy elements: 16–18% Cr, 0.60–1.00% Ni and 0.80–1.30% Mo. P20 only has 1.40–2.00% Cr. It is not overpriced. Every gram of these alloy metals adds material cost.

A:

Yes. Its pre-hardened hardness is 28–34 HRC. If you do quenching and low-temperature tempering by yourself, it can reach 48–52 HRC. However, higher hardness will lower its toughness and anti-rust performance. This is a basic material rule. We do not suggest sacrificing its core corrosion resistance just for higher hardness.
 
 

Conclusion

Many buyers pick mold steel that works just okay but is hard to process. If you are unsure which application fits 1.2316 Stainless Mold Steel, what polish level you need, and which hardness to order to save the most cost, engineers from Keyspark Steel can work out a suitable material plan based on your mold demands. We help you avoid unnecessary extra spending.
 
 
 

📧 Email: Sales@keysparksteel.com
📱 Mobile/WhatsApp: +86 150 2405 6480

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