Stainless Steel Grades
When selecting stainless steel jewelry, it is important for consumers to recognize that quality can vary significantly among different grades.
Most jewelry labeled as stainless steel is typically manufactured from 304 Grade, which is considered the basic among commonly available grades. Grade 316 offers enhanced properties compared to Grade 304. However, 316L stands out as the premium option. It is worth noting that the difference between Grade 316 and 316L is sometimes obscured by marketing practices, with some products labeled “316” being marketed as “316L.” This can be misleading to consumers seeking the best available option. While 316L is generally regarded as the superior choice for stainless steel jewelry, be aware that not all items advertised as 316L necessarily meet this standard.
| Property | 316 L (Our Steel) | 316 | 304 |
|---|---|---|---|
| Pitting Corrosion Resistance | Excellent | Excellent | Poor |
| Inter granular Corrosion Resistance | Excellent | Fair | Fair |
| Crevice Corrosion Resistance | Excellent | Excellent | Fair |
| Cost | Slightly High | High | Low |
| Hypo allergenic | Yes Very Sensitive Skin | Yes Sensitive Skin | Yes Sensitive Skin |
| Aesthetic Look | Bright & Glossy but more stable overtime | Bright & Glossy | Bright & Glossy |
| Yield Strength | High (290 Mpa) | High (290 Mpa) | Fair (215 Mpa) |
| Tensile Strength | High (570Mpa) | High (570Mpa) | Fair (505 Mpa) |
| Carbon Content | Ultra Low (.03%) | Low (.08%) | Low (.08%) |
| Main Elements | 16% Cr 10% Ni 2% Mo | 16% Cr 10% Ni 2% Mo | 18% Cr 8% Ni |
The science behind Tarnishing and The Nickel Dilemma
Pitting Corrosion
Pitting corrosion is a localized form of damage that results in deep pits or holes on the surface of jewellery. This type of corrosion occurs when corrosive agents such as chlorides, salt water, or acids attack the metal, leading to the formation of concentrated spots of deterioration.
Sources of Corrosive Agents
Several substances that we commonly encountered daily can act as corrosive agents. These sources are often found in our everyday routines and environments. Tap water, for instance, may contain minerals and chemicals that initiate corrosion. Water from hot tubs, swimming pools, and sea is especially rich in chlorides, which are known to accelerate pitting corrosion.
In addition to water-based sources, various personal care products frequently used can also introduce corrosive chemicals. Bath soaps, shampoos, lotions, and detergents may contain ingredients that react with metals. Perfumes, hand sanitizers, and deodorants often have compounds that promote corrosion. Even perspiration from our own bodies can create an acidic environment, further increasing the risk of pitting corrosion on jewellery.
316L– Exhibits excellent resistance to pitting corrosion owing to its 2–3% molybdenum content.
316-Demonstrates excellent performance for the same reason as 316L.
304-Offers poor resistance due to the absence of molybdenum.
What to Choose?
For regular exposure to these elements it is recommended to choose 316L or 316 grades.
Intergranular Corrosion
Intergranular Corrosion is a type of corrosion that occurs along the grain boundaries of the metal particularly the welded points. Also known as the “welded decay”. This happens when Carbide forms during the welding process that weakens the joints.
The Impact of Carbon Content on Carbide Deposits and Weld Decay:
When crafting a piece of jewellery, a considerable amount of welding and soldering is involved. The precise number of components that require welding depends largely on the complexity of the design. For simpler pieces, there may be only a few joints, whereas more intricate designs will naturally involve a higher number of welded or soldered sections. Each joint contributes to the overall strength, durability, and appearance of the finished piece.
Carbide deposits in stainless steel are directly influenced by the material’s carbon content.When the carbon content is lower, there are fewer carbide deposits formed during welding. This reduction in carbide formation leads to less weld decay.
316L– Excellent weldability, classified as ULTRA Low Carbon .03% Carbon
316– Good weldability, classified as Low Carbon .08% Carbon
304– Good weldability, Classified as Low Carbon .08 % Carbon
What to choose?
Choose 316L for chain based and complex jewelry designs
Choose 316 and 304 for band rings, plain rings and bangles.
Crevice Corrosion
Crevice corrosion is a specific type of corrosion that occurs within tight or narrow gaps found in jewellery pieces. These restricted spaces can easily trap moisture and chemicals, leading to localized corrosion that may compromise the integrity and appearance of the jewellery.
Common Locations of Crevice Corrosion:
Bails (Fixed, movable, enhancers) Gallery
Airline
Channel
Clasp(Lobster clasp, barrel, bolo, box, fish hook, toggle, spring ring, swivel)
Spacers
These components often feature small crevices making them particularly susceptible to crevice corrosion.
316L-Superoir resistance due to High Chromium(16%-18%) and added Molybdenum(2%-3%)
316– Excellent protection for the same reason as 316L.
304-Medium protection due to the absence of Molybdenum
What To Choose?
Choose 316 L for more detailed and intricate design.
Hypoallergenic: The Nickel Dilemma
Nickel is recognized as the most common cause of metal allergies, estimated to affect approximately 10–20% of people. This presents a particular concern for individuals who experience sensitivity or allergic reactions when exposed to nickel. Stainless steel grades such as 316L, 316, and 304 all contain nickel as part of their composition.
So why is stainless steel considered hypoallergenic?
The hypoallergenic nature of stainless steel depends on its ability to contain nickel to its structure and resist different forms of corrosion, including pitting, intergranular, and crevice corrosion. If a stainless steel grade offers high resistance to these corrosive processes, nickel remains securely bound within its matrix. This containment greatly reduces the likelihood of nickel leaching out and coming into contact with skin, thereby lowering the risk of allergic reactions.
Among the various grades, 316L stainless steel is notable for its superior binding of nickel, making it less likely to release nickel compared to other grades. While 316 and 304 stainless steel also provide good corrosion resistance and are generally more affordable, they do not match the level of nickel containment offered by 316L.
Which one to Use?
For individuals with mild sensitivities to nickel, 316 and 304 stainless steel are usually adequate for everyday use. However, for those seeking the highest level of protection, 316L stainless steel is recommended. Its enhanced nickel stability makes it the preferred choice for people with very sensitive skin.
Choose the Right Finish
It is essential to take into account not only the grade of stainless steel but also the applied finish. The longevity and resilience of each piece are largely determined by the quality of its finish, which acts as the primary protective barrier. Although PVD (Physical Vapor Deposition) coatings are frequently utilized for precious metals such as gold and silver, we also employ this advanced coating technique for our fashion steels. We prioritize the use of this premium quality process over electroplating, as it provides superior durability and performance despite higher costs.
| PVD (Our Finish) | Electro plating | |
|---|---|---|
| Bonding Agent ( Use to adhere Gold to stainless Steel) | Titanium | Nickel |
| Corrosion Resistant | Excellent | Limited |
| Color Retention | Excellent | Limited |
| Scratch Resistance/ Hardness | Excellent (10x) | Limited |
| Cost | Cheaper on the long run | Cheaper initial investment |
| Environmentally Friendly | Yes (No Toxic Chemicals) | No (Hazardous Waste) |
| Coat Thickness | Thick 3 Coats (.03-.08 micron) | Thin (.1-.2 micron) |
| Color Options | Limited to Specific Color Options | Unlimited Color Possibilities |
| Adhesion to Stainless | Strong | Weak |
Comparison With Other Materials
| 316L | Gold | Silver | Titanium | |
| Corrosion Resistance | Excellent | Moderate | Moderate | Excellent |
| Durability | High | Moderate | Low | High |
| Hypo allergenic | Yes | Yes | Yes | Yes |
| Cost | Affordable | Moderate | Expensive | Moderate |
| Maintenance | Low | High | Moderate | Low |
| Weight | Medium | Light | Medium | Light |