QD is a professional stainless steel caster. With years of industry experience, we help you quickly identify the most suitable stainless steel material. This avoids losses caused by improper material selection.
What will your part be exposed to?
The corrosion resistance of stainless steel depends mainly on its composition and the environment where it is used. Different environments have different requirements for stainless steel. Below are common environments and recommended stainless steel grades:
| Use Environment | Recommended Grade | Characteristics and Reasons |
| Air, Fresh Water | 304 | Cost-effective. Offers good corrosion resistance and formability. Suitable for mild environments. |
| Salt, Acid, or Chemicals | 316 | Contains Mo. Significantly improves resistance to pitting and crevice corrosion. Suitable for more corrosive environments. |
| High Temperature Environment | 310S | High chromium content. Excellent oxidation and creep resistance. Suitable for continuous high-temperature operation. |
| High Strength, High Hardness Requirements | 410, 420 | Martensitic stainless steel. Hardness and strength can be increased through heat treatment. But corrosion resistance is relatively low. |
| General Purpose, Cost-Sensitive | 430 | Ferritic stainless steel. Lower cost. Average corrosion resistance. Suitable for dry or indoor environments. |
304 Stainless Steel: Contains 18%-20% chromium and 8%-10% nickel. It performs reliably in mild environments. But if exposed to chlorides (like salt water), pitting may occur.
316 Stainless Steel: It contains an added 2%-3% molybdenum. This significantly improves its resistance to chloride ions. It suits marine and chemical environments.
Other Conditions: If your part contacts strong acids (like sulfuric or hydrochloric acid), higher-grade stainless steel such as 317L or duplex stainless steel 2205 may be needed. We can provide tailored suggestions based on your specific conditions.
Tips: Special Note on Welding
If the part requires welding, pay close attention to selecting low-carbon grades. Regular stainless steel can suffer from carbide precipitation in the weld area during welding. This causes intergranular corrosion and reduces corrosion resistance.
Solution:
- Select low-carbon grades like 304L or 316L. The “L” means low carbon. Their carbon content is kept below 0.03%. This effectively prevents corrosion issues after welding.
- We often recommend L-grade stainless steel to our clients. Using advanced welding techniques, we ensure the welded areas perform as well as the base material.
Application Range of Other Common Stainless Steels
Besides 304 and 316, the following stainless steel grades are widely used in specific fields:
| Grade | Type | Main Characteristics | Typical Applications |
| 410 | Martensitic | Can achieve high hardness through heat treatment. Average corrosion resistance. | Cutting tools, bearings, mechanical parts |
| 420 | Martensitic | Higher carbon content provides better hardness and wear resistance. But corrosion resistance is poorer. | Surgical instruments, molds, cutlery |
| 430 | Ferritic | Low cost, relatively weak corrosion resistance. Easy to form. | Home appliance trim, indoor building materials, tableware |
| 2205 | Duplex | Combines advantages of austenite and ferrite. High strength, resists stress corrosion and pitting. | Chemical equipment, offshore platforms, petroleum pipelines |
| 317L | Austenitic | High molybdenum content. Better resistance to acid and chloride corrosion than 316. | Strong acid environments, pollution control equipment |
Material Selection Tips:
- For parts requiring wear resistance and strength, 410 and 420 are the preferred choices, but rust prevention measures are necessary.
- In scenarios with strict cost control, 430 can be an alternative, but only in low corrosion environments.
- QD maintains stock of various grades and offers quick sampling services to help you verify material suitability.
Why is Stainless Steel “Stainless”?
The “stainless” property comes from a protective chromium oxide layer (passive film) on its surface. When the chromium content is at least 10.5%, this film can self-repair and prevent further oxidation. However, in specific environments (like high chloride levels or mechanical damage), the film can break down, leading to localized corrosion.
Common Types of Corrosion:
- Pitting Corrosion: Localized, small-hole type corrosion. Common in chloride-containing environments.
- Crevice Corrosion: Occurs inside gaps, caused by differences in oxygen concentration.
- Stress Corrosion Cracking: Happens under the combined action of tensile stress and a corrosive medium.
Protective Measures:
- Select the appropriate grade (e.g., 316 resists pitting corrosion).
- Optimize designs to avoid crevices.
- Perform regular maintenance and cleaning.
We not only supply materials but also provide corrosion prevention design and maintenance advice. We ensure the part’s performance throughout its entire service life.
QD: Your Professional Material Selection Partner
Experience is crucial in stainless steel selection. QD foundry offers these advantages:
Expert team: Our engineers master the properties of various stainless steels. They can recommend the most cost-effective and efficient grade based on your operating environment.
Free material selection advice: Just provide the part’s service conditions (like temperature, medium, stress). We will provide a professional report.
Quality assurance: All materials meet international standards (like ASTM, GB). We provide test certificates.
Fast response: We offer efficient support from inquiry to delivery. This helps shorten your project timeline.
Still struggling whether to choose 304, 316 or other stainless steel grades? Just tell us your part’s operating environment, and our experts will provide free material selection advice.
FAQ
1. What is the main difference between 304 and 316 stainless steel?
316 contains 2%-3% more molybdenum than 304. This makes it resist pitting and crevice corrosion better. It is especially suitable for chloride environments.
2. Why choose L-grade for welding?
L-grade has lower carbon content. It prevents intergranular corrosion caused by carbide precipitation during welding. This ensures the weld’s durability.
3. How to determine which stainless steel my environment requires?
Key factors include: contact medium (like water, acid, salt), temperature, stress condition, and whether welding is needed. QD provides free environmental assessment services.
4. Can QD provide custom stainless steel parts?
Yes. We support full-process customization from material selection, casting, machining to surface treatment. This ensures the parts meet your working condition requirements.
5. How to balance cost and performance when selecting stainless steel?
We recommend prioritizing lifecycle cost: higher-priced materials may have higher initial investment but can reduce replacement and maintenance expenses. QD can help you conduct a comprehensive cost analysis.