# Category: Materials know-how - [Index of our articles](https://menet-trend.hu/en/nonox-world/index-of-our-articles.md) — Every NONOX World article in one place, in alphabetical order: 97 links covering fasteners, stainless and acid-resistant materials, tools, chains, wire ropes, pipe fittings and building hardware. Whatever you are looking for, start here — the whole blog, from galling to concrete screws, on a single page. - [Wastewater never stops](https://menet-trend.hu/en/nonox-world/wastewater-never-stops.md) — A conversation with the technical director of a partner that designs and builds industrial and municipal wastewater treatment systems: why carbon steel is banned around food, what OKS-250 paste solved, and why the non-return valve is all but forbidden in industry. - [Useful advice on preserving stainlessness](https://menet-trend.hu/en/nonox-world/useful-advice-on-preserving-stainlessness.md) — How can something be called stainless if it is prone to rusting? Practical advice on protecting the surface oxide layer, on why stainless steel must never meet carbon steel, and a table of 60 chemicals with their effect on A2 and A4 grades. - [OKS-250 anti-galling paste](https://menet-trend.hu/en/nonox-world/oks-250-anti-galling-paste.md) — Galling is not a material defect and not corrosion – but with stainless threads it can happen on the very first tightening. What causes it, how to prevent it with heterogeneous A2/A4 pairings, slower tightening and clean threads, and what OKS 250 anti-galling paste does. Plus our anti-galling warranty. - [Chemical composition of stainless steels II](https://menet-trend.hu/en/nonox-world/chemical-composition-of-stainless-steels-ii.md) — According to DIN EN ISO 3506: the chemical composition of austenitic (A1–A5), martensitic (C1, C3, C4) and ferritic (F1) stainless steels in mass percentages of carbon, silicon, manganese, phosphorus, sulphur, chromium, molybdenum, nickel and copper, with the twelve footnotes on sulphur, molybdenum, nickel and the stabilising titanium and niobium. - [Mechanical properties of fasteners in the martensitic steel group](https://menet-trend.hu/en/nonox-world/mechanical-properties-of-fasteners-in-the-martensitic-steel-group.md) — According to DIN EN ISO 3506: the mechanical properties of martensitic (C1, C3, C4) and ferritic (F1) stainless fasteners — tensile strength, 0,2% yield strength, elongation at fracture and hardness in HB, HRC and HV — plus the length limits, the thread diameter range and the temperature caveats to agree with your supplier. - [Chemical composition of stainless steels](https://menet-trend.hu/en/nonox-world/chemical-composition-of-stainless-steels.md) — An extract from ISO 683-13:1986: the chemical composition of ferritic, martensitic and austenitic stainless steels, with maximum mass percentages for carbon, silicon, manganese, phosphorus and sulphur, plus nitrogen, aluminium, chromium, molybdenum, niobium, nickel, selenium, titanium and copper, and the steel group codes that map them to the F1, C and A1–A5 grades. - [Chemical composition of stainless steels intended for cold forming](https://menet-trend.hu/en/nonox-world/chemical-composition-of-stainless-steels-intended-for-cold-forming.md) — An extract from ISO 4954 : 1993: the chemical composition of ferritic, martensitic and austenitic stainless steels intended for cold forming, with mass percentages for carbon, silicon, manganese, phosphorus, sulphur, chromium, molybdenum and nickel, plus the steel group codes that map them to the A2, A4 and A5 grades. - [Stainless and acid-resistant steels used in Germany](https://menet-trend.hu/en/nonox-world/stainless-and-acid-resistant-steels-used-in-germany.md) — A reference table of the stainless and acid-resistant steels used in Germany: material number, the designation under the VDEh standard that preceded DIN, indicative average analysis for carbon, silicon, manganese, chromium, nickel and molybdenum, and a typical example of use for every grade. - [The corrosion resistance of the A2 stainless and A4 acid-resistant screw raw materials](https://menet-trend.hu/en/nonox-world/the-corrosion-resistance-of-the-a2-stainless-and-a4-acid-resistant-screw-raw-materials.md) — Austenitic stainless and acid-resistant steels belong in the category of active corrosion protection thanks to their alloying materials. Even so, they can corrode in practice. Rust contamination, surface, local, contact, stress and mechanical corrosion, and how to guard against each. - [Corrosion-resistant alloys](https://menet-trend.hu/en/nonox-world/corrosion-resistant-alloys.md) — Protective coatings only protect while they remain intact. The other fundamental method of protection against corrosion is alloying, thanks to which stainless and acid-resistant steels came into being. From iron-carbon alloys to the welding and standardisation of A2 and A4 grades. - [How to protect against rust](https://menet-trend.hu/en/nonox-world/how-to-protect-against-rust.md) — By definition, corrosion is the destruction of metals by an electrochemical process. In a dry medium iron does not rust, yet corrosion causes an estimated HUF 50 billion of damage a year in Hungary. Local cells, protective coatings, galvanising and cathodic protection explained. - [Galling of stainless screws](https://menet-trend.hu/en/nonox-world/galling-of-stainless-screws.md) — NOT a material defect! NOT caused by corrosion! NOT a common phenomenon, but it can happen. With austenitic screws the thread can seize as if welded, already during the first tightening. What causes galling, and which methods reliably prevent it? - [Steels and their properties](https://menet-trend.hu/en/nonox-world/steels-and-their-properties.md) — Iron is an important element of living organisms and one of our most heavily used industrial materials, especially its alloy with carbon: steel. From classification and the effect of carbon to the alloying elements behind corrosion-resistant and acid-resistant grades, here is what shapes the properties of steels. - [Steels and their properties II](https://menet-trend.hu/en/nonox-world/steels-and-their-properties-ii.md) — Structural steels. Materials such as steel are things we encounter primarily in practice, as users, so it is worth discussing some of their properties on the basis of their fields of application. Non-alloy structural steels are usually supplied in the hot-rolled or forged condition. - [Heat treatment](https://menet-trend.hu/en/nonox-world/heat-treatment.md) — Heat treatment is a technological operation consisting of controlled heating and heat transfer and/or cooling, by which the properties of products can be modified to suit their application. There are certain heat treatments that are used for a particular alloy family – for example for stainless and acid-resistant steels. - [How to avoid galling of stainless steel fasteners](https://menet-trend.hu/en/nonox-world/how-to-avoid-galling-of-stainless-steel-fasteners.md) — With NONOX stainless steel screw joints, galling of rough surfaces can still cause problems even today. It is not uncommon for the phenomenon to be assumed to be caused by corrosion; in contrast, other triggering causes usually lie in the background, such as coarse thread machining or other surface damage. - [Designations of stainless steels](https://menet-trend.hu/en/nonox-world/designations-of-stainless-steels.md) — Extract from standard DIN EN ISO 3506. Steel groups and strength classes are designated by a sequence of letters and numbers consisting of 4 characters. The letters denote the general classification of the steel groups: A = austenitic steels, C = martensitic steels, F = ferritic steels. - [20 points to follow to prevent galling of austenitic (stainless and acid-resistant) screws](https://menet-trend.hu/en/nonox-world/20-points-to-follow-to-prevent-galling-of-austenitic-stainless-and-acid-resistant-screws.md) — Galling of stainless and acid-resistant screws is not caused by a material defect, but by mechanical irregularities and/or failure to follow the assembly technology. You can find out here, point by point, what that technology is: handle the screws carefully, and avoid every possibility of mechanical damage to them. --- HTML: