Silicon bronze bolts vs stainless steel fasteners

 

Silicon bronze bolts vs stainless steel fasteners

What is silicon bronze?

Silicon bronze is a brass alloy which contains a significant addition of silicon. This low lead, alloy exhibits superior corrosion resistant properties due to the addition of silicon. Contemplated to be one of the easiest copper based alloys to form/pour, silicon bronze bolts are readily weldable, joinable as well as soldered, and cast. Moreover, bolts produced from this alloy not only has good resistance to corrosion, but they exhibit high tensile strength and formability properties. Silicon bronze has a slightly higher density as compared to stainless steels in general. Many woodworkers prefer using silicon bronze bolts as they are often regarded as one of the better looking copper alloys. Its superior formability properties in conjunction with its aesthetics permit these silicon bronze fasteners to be used in many applications involving decorative and architectural uses. Its attractive reddish-gold colouration makes them a favoured set of fasteners amongst various craftsmen. These fasteners tend to resists deformation due to its high tolerance of cycle loading as well as fatigue induced stress. However, in the event of silicon bronze fasteners breaking, the alloy first gets deformed by indicating certain visual confirmatory signs such as elongated holes, twists and bends. Thus rendering the user to understand that these fasteners need to be replaced. Similar to most copper alloys, silicon bronze is conductive, unlike many stainless steel grades which have very low heat and thermal conduction properties.

What is stainless steel?

Stainless steel is a chromium containing ferrous alloy. This chemistry of stainless steel is what prevents the fasteners from getting rusted. While stainless steel in general envelopes many stainless steel grades, austenitic alloys 304 and 316 are amongst the most popular grades. Speaking of their appearance, stainless steel fasteners generally silverish in colour, unless they have been coated by plating with zinc or coated with colours. An advantage stainless steel grades have is that their chemistry can be modified to suit the requirements of the applications. For instance, welding would require a low carbon content eg. grade 309S or 304L. Or if the application requires high creep resistance, the carbon content is to be increased eg. grade 304H or 309H. Sulfur containing grade 303 is an alloy that has good machinability properties. When exposed to elevated temperatures (800 to 1500°F) in the chromium carbide precipitation range, grade 321SS resists intergranular corrosion. In general, stainless steels are considered to be very versatile on account of their usability across a wide range of temperatures. To exemplify, grade 304 is a stainless steel alloy that could be used in cryogenic temperature settings, while grades 321 and 347, could be used up to a temperature of 1500°F and grade 310 can resist oxidation at 2010°F when exposed to mildly cyclic conditions.

Silicon bronze bolts vs stainless steel fasteners

With the exception of being a decorative alloy, silicon bronze bolts are used in applications involving the marine industry as well as in electrical components, and chemical processing equipment. Their enhanced resistance to corrosion in both freshwater and saltwater is what makes these bolts highly useful for marine applications. Silicon bronze bolts are also resistant to alkalis, acids, fog/mist, and organic chemicals. However, a shortcoming of using this alloy is that they are susceptible to attack when exposed to nitric acid, chromates, sulfides, ferric chloride, as well as other oxidizing salts. Different stainless steels have varying reactions to chemicals. For instance, grade 317LMN is an alloy that resists attack in sulfuric acid, acidic chlorine, hydrochloric acid, and phosphoric acid, whereas, stainless steel Alloy 309 could be used in sulfur-containing atmospheres up to 1832°F. Another important property of austenitic stainless steel grades, especially grade 347 is that the alloy possesses good low temperature toughness in addition to superior resistance to oxidation.

Being an anti-biofouling alloy, Silicon bronze bolts are is inherently antimicrobial. Hence, they can passively be defensive against the spread of germs. In the case of stainless steel, grade 316 is referred to as a hygienic alloy, proving to be useful in industries that have non-toxicity as their primary requirements, such as the pharma & food and beverage. A major flaw of silicon bronze is that this alloy is expensive, unlike stainless steel grade which is one of the most economical metals with adequate resistance to corrosion and good mechanical strength.

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