{"id":948,"date":"2026-08-17T06:26:58","date_gmt":"2026-08-17T06:26:58","guid":{"rendered":"https:\/\/junruims.com\/?p=948"},"modified":"2026-08-17T07:00:08","modified_gmt":"2026-08-17T07:00:08","slug":"injection-mold-steel-for-daily-plastic-products","status":"publish","type":"post","link":"https:\/\/junruims.com\/index.php\/2026\/08\/17\/injection-mold-steel-for-daily-plastic-products\/","title":{"rendered":"6 Best Injection Mold Steel for Daily Plastic Products | Ultimate Cost Comparison"},"content":{"rendered":"\n

When selecting injection mold steel for daily plastic products, factors including mold service life, product surface quality and overall production cost need full consideration. In the development of injection mold steel for daily plastic products<\/strong>(such as plastic cups, storage containers, food containers, personal care product packaging, and toys), the choice of mold steel directly determines mold life, product quality, and production costs.<\/p>\n\n\n\n

Everyday plastics are mostly general-purpose or standard engineering plastics such as PP, PE, ABS, PS, PVC, and PET. Production is characterized by large batch sizes, long production cycles, and cost sensitivity. The following is an analysis of commonly used injection mold steel for daily plastic products<\/strong> and their cost-effectiveness.<\/p>\n\n\n\n

\"injection<\/figure>\n\n\n\n

Which injection mold steel for daily plastic products<\/strong> offers the best cost-performance ratio?<\/h2>\n\n\n\n

1. Economical Entry-Level Steel: S50C\/45# Carbon Structural Steel<\/p>\n\n\n\n

Material: High-quality medium-carbon structural steel; non-alloy mold steel.<\/p>\n\n\n\n

Hardness: HRC 28\u201332 after quenching and tempering; supplied unhardened and requires in-house heat treatment.<\/p>\n\n\n\n

Properties: Extremely low cost, good machinability, and easy to weld and repair; however, it has poor wear resistance, weak corrosion resistance, is prone to rust, has relatively low hardness, and a short service life.<\/p>\n\n\n\n

Advantages: Lowest material and processing costs; easy to procure.<\/p>\n\n\n\n

Disadvantages: Extremely short service life; prone to wear and rust; cannot meet the requirements for medium-to-large production runs or basic aesthetic standards.<\/p>\n\n\n\n

Applications: Daily necessities with minimal requirements and small production runs (\u2264100,000 mold cycles), such as disposable tableware, inexpensive toys, and low-precision plastic brackets. Suitable only for soft, non-corrosive, general-purpose plastics like PP and PE with low aesthetic requirements.<\/p>\n\n\n\n

2. Mainstream General-Purpose Pre-hardened Steel: P20 (Domestic 3Cr2Mo)<\/p>\n\n\n\n

Material: American standard pre-hardened plastic mold steel; the industry\u2019s most basic and versatile option.<\/p>\n\n\n\n

Hardness: Factory-pre-hardened to HRC 28\u201336; requires no subsequent heat treatment and can be machined directly.<\/p>\n\n\n\n

Performance: Balanced overall performance, easy to machine, moderate polishability (Ra 0.4\u20130.8 \u03bcm), good toughness, and moderate price; moderate wear resistance, but not corrosion-resistant.<\/p>\n\n\n\n

Advantages: Pre-hardened, eliminating the need for heat treatment; high machining efficiency; controllable costs; meets 80% of the basic requirements for conventional daily-use products.<\/p>\n\n\n\n

Disadvantages: Relatively low hardness, prone to wear during high-volume production; polishing achieves only a standard matte finish, unsuitable for high-gloss or transparent parts; prone to rust when exposed to moisture or corrosive plastics.<\/p>\n\n\n\n

Applications: As a widely used injection mold steel for daily plastic products<\/strong>, P20 is suitable for small to medium production runs (\u2264300,000 mold cycles) and everyday items with standard appearance, such as conventional plastic basins, standard storage bins, non-high-gloss home appliance housings, and toy bodies. Suitable for the vast majority of general-purpose plastics, including PP, PE, PS, ABS, and non-reinforced PA.<\/p>\n\n\n\n

3. Upgraded General-Purpose Grade: 718H (Domestic 3Cr2NiMo)<\/p>\n\n\n\n

Material: An upgraded version of P20, with added nickel, resulting in significantly improved purity and uniformity.<\/p>\n\n\n\n

Hardness: Pre-hardened to HRC 33\u201338 at the factory, offering higher hardness with uniform distribution.<\/p>\n\n\n\n

Performance: Superior strength, wear resistance, and polishability (Ra 0.2\u20130.4 \u03bcm) compared to P20; stable performance in large-sized molds; good toughness and strong resistance to deformation.<\/p>\n\n\n\n

Advantages: As the most versatile injection mold steel for daily plastic products<\/strong>, 718H handles medium- to large-volume production (\u2264500,000 mold cycles) of consumer goods with certain aesthetic requirements, such as high-quality storage boxes, plastic buckets, transparent containers, personal care product bottles, and medium-sized molds with complex structures; suitable for plastic products made from PP, PE, ABS, PS, PC, PMMA, PET, and other materials.<\/p>\n\n\n\n

Disadvantages: Approximately 20%\u201330% more expensive than P20; still lacks corrosion resistance and is not suitable for corrosive plastics such as PVC.<\/p>\n\n\n\n

Applications: Medium- to large-volume production (\u2264500,000 mold cycles) of consumer goods with certain aesthetic requirements, such as high-quality storage boxes, plastic buckets, transparent containers, personal care product bottles, and medium-sized molds with complex structures; suitable for plastic products made from PP, PE, ABS, PS, PC, PMMA, PET, and other materials.<\/p>\n\n\n\n

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4. High-Gloss Pre-hardened Steel: NAK80<\/p>\n\n\n\n

Material: High-grade pre-hardened mirror-finish mold steel produced via electroslag remelting, with minimal impurities.<\/p>\n\n\n\n

Hardness: Factory-pre-hardened to HRC 37\u201343; no heat treatment required.<\/p>\n\n\n\n

Performance: Excellent mirror-finishing capabilities (Ra \u2264 0.05 \u03bcm); maintains good surface quality after EDM without requiring secondary polishing; high dimensional stability.<\/p>\n\n\n\n

Advantages: Top-tier mirror finish, easy machining, high precision, and free of pitting or pinholes.<\/p>\n\n\n\n

Disadvantages: High cost (1.5\u20132 times that of P20); wear resistance comparable to standard pre-hardened steel; poor cost-effectiveness for non-high-gloss applications.<\/p>\n\n\n\n

Applications:When ultra-high surface finish is required from injection mold steel for daily plastic products<\/strong>, NAK80 is ideal for high-finish, high-transparency consumer goods, such as high-end cosmetics packaging, transparent food containers, optical-grade plastic components, and high-gloss enclosures; suitable for transparent\/high-gloss plastics such as PC, PMMA, and PSU.<\/p>\n\n\n\n

5. Corrosion-Resistant Mirror-Finish Steel: S136 (Modified 4Cr13)<\/p>\n\n\n\n

Material: High-chromium martensitic stainless steel, containing 13.5%\u201314.5% Cr, produced via ultra-pure smelting.<\/p>\n\n\n\n

Hardness: HRC 48\u201355 after quenching and tempering; heat treatment required.<\/p>\n\n\n\n

Performance: Extremely high corrosion resistance; mirror polishing can achieve ultra-mirror finish (Ra \u2264 0.01 \u03bcm); excellent wear resistance; long service life (\u2265 1 million cycles).<\/p>\n\n\n\n

Advantages: Rust-proof and corrosion-resistant; ultra-mirror finish; ultra-high wear resistance; long service life; suitable for demanding applications.<\/p>\n\n\n\n

Disadvantages: Expensive (2\u20133 times the price of P20), requires heat treatment, difficult to machine, and high production costs.<\/p>\n\n\n\n

Applications: High-end, highly corrosive, and long-life consumer goods, such as food-grade packaging, high-end cosmetic bottles, and preforms.<\/p>\n\n\n\n

6. Economical Corrosion-Resistant Steel: 4Cr13 (Simplified Domestic Version of S136)<\/p>\n\n\n\n

Material: Martensitic stainless steel; an economical alternative to S136.<\/p>\n\n\n\n

Hardness: HRC 45\u201352 after heat treatment.<\/p>\n\n\n\n

Performance: Good corrosion resistance; polishable to Ra 0.2\u20130.4 \u03bcm; wear resistance superior to that of pre-hardened steel; lower price than S136<\/p>\n\n\n\n

Advantages: Corrosion-resistant, wear-resistant, and lower cost than S136; meets basic requirements for corrosion resistance and high gloss.<\/p>\n\n\n\n

Disadvantages: Requires heat treatment; polishing quality is inferior to S136\/NAK80; price is higher than 718H.<\/p>\n\n\n\n

Applications: Daily-use products requiring rust prevention or protection against mild corrosion and with moderate aesthetic requirements, such as yogurt cup lids, standard cosmetic bottles, and food-contact molds that do not require a super-mirror finish.<\/p>\n\n\n\n

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Which steel offers the best cost-performance ratio for mold making?<\/p>\n\n\n\n

Considering the three core factors\u2014production characteristics, quality requirements, and cost control\u2014for consumer plastic products, 718H is the top injection mold steel for daily plastic products<\/strong> in terms of overall value; P20 is the preferred entry-level option for limited budgets; and S136\/4Cr13 is specifically designed for corrosion-resistant applications.<\/p>\n\n\n\n

1. The King of Overall Value\u2014718H.<\/p>\n\n\n\n

Most consumer plastics are produced in medium to large batches. 718H offers superior wear resistance and service life compared to P20, making it capable of withstanding long-term mass production wear; its polishability meets the matte to semi-gloss finish requirements for consumer goods (storage boxes, bottle bodies, containers, etc.), eliminating the need for expensive mirror-finish steel.<\/p>\n\n\n\n

Optimal balance of cost and efficiency. Pre-hardened and heat-treatment-free, it significantly shortens the machining cycle and reduces heat treatment risks and costs.<\/p>\n\n\n\n

Priced only 20%\u201330% higher than P20, it offers a 40%\u201350% longer service life, greater quality consistency, and lower per-mold cost allocation, resulting in a total cost of long-term mass production that is far lower than that of P20.<\/p>\n\n\n\n

It offers the broadest range of applications, covering the vast majority of plastics used in daily consumer goods\u2014including PP, PE, ABS, PS, PC, and PET\u2014and is suitable for standard to medium aesthetic requirements, medium-to-large production volumes, and moderately complex molds. It meets nearly 80%\u201390% of daily consumer goods mold-making needs.<\/p>\n\n\n\n

2. The economical choice for limited budgets\u2014P20.<\/p>\n\n\n\n

If the product involves small to medium production runs (\u2264300,000 mold cycles), has low aesthetic requirements, is made of pure PP\/PE soft plastics (such as ordinary disposable containers), and is subject to strict budget constraints, P20 is the most economical injection mold steel for daily plastic products<\/strong>.<\/p>\n\n\n\n

It offers the lowest procurement and processing costs, requires no heat treatment, and processes quickly, meeting basic production needs. However, users must accept its shortcomings, including short service life, susceptibility to wear, lack of corrosion resistance, and average appearance.<\/p>\n\n\n\n

3. High-End Specialized Applications\u2014NAK80\/S136.<\/p>\n\n\n\n

NAK80 or S136 should only be selected when the product requires ultra-transparency or a mirror-like finish (such as transparent cases for high-end cosmetics) or is exposed to highly corrosive materials (PVC, flame-retardant, food-grade, or medical-grade), and is produced in large volumes.<\/p>\n\n\n\n

These steels offer top-tier performance but come at a high cost; using them for ordinary consumer goods would be a waste of resources and does not represent a cost-effective choice.<\/p>\n\n\n\n

4. For Temporary\/Test Use Only\u2014S50C\/45#.<\/p>\n\n\n\n

These are absolutely not recommended for mass-production molds for daily-use products. They have a very short service life, are prone to rust, and offer inconsistent quality. While they may save money in the short term, the long-term costs\u2014including mold repairs, replacements, and scrapping\u2014result in higher overall expenses.<\/p>\n\n\n\n

In summary, 718H represents the pinnacle of cost-effectiveness among injection mold steel for daily plastic products<\/strong>\u2014delivering “long service life, ease of machining, consistent quality, and broad compatibility” at a moderate cost, making it the optimal general-purpose choice for mass-producing daily consumer goods.<\/p>\n\n\n\n

You can also read our step\u2011by\u2011step guide about\u00a0injection mold\u00a0<\/a>development to know the full mold\u2011making workflow<\/p>\n","protected":false},"excerpt":{"rendered":"

When selecting injection mold steel for daily plastic products, factors including mold service life, product surface quality and overall production cost need […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-948","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/posts\/948","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/comments?post=948"}],"version-history":[{"count":5,"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/posts\/948\/revisions"}],"predecessor-version":[{"id":961,"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/posts\/948\/revisions\/961"}],"wp:attachment":[{"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/media?parent=948"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/categories?post=948"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/junruims.com\/index.php\/wp-json\/wp\/v2\/tags?post=948"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}