UGI® 4062 Solution Annealed, Spring Wire

UGI® can be used in most of the applications where the following grade types are used 1.4301 (AISI 304), 1.4307 (AISI 304L) or 1.4310 (AISI 302/301). Thes applications are:

UGI® 4062 is suitable for cold transformation by means of conventional methods.

UGI® 4062 can be cold work hardened more than the 1.4301 austenitic grade (AISI 304) which is more stable; on the contrary, UGI® 4062 can be cold work hardened similarly to the 1.4310 austenitic grade (AISI 302). As from 40 % cold deformation approximately, one part of the austenite gradually transforms into martensite, which thus increases the magnetic characteristic of the grade. A new solution heat treatment between 950 and 1,050 °C allows the ductility of UGI® 4062 to be restored.

Wire drawing: Typical work hardening curve is avaolable on the picture part of the datasheet above.

Bending – Forming: The cold transformed wire, in 2D condition, is suitable for bending. For instance, wires with 10 mm in diameter were bent to 180° degrees on a radius which was 2.5 times bigger than the diameter of the wire. We observed correct appearance, with low roughness, of the extended face, without orange peel surface, when compared to 1.4307 (304L).

Spring manufacturing: UGI® 4062 can be used in cold work hardened wire to manufacture springs. The stiffness of these springs exceeds that of the springs made of 1.4310 by 20 to 25 %. A stabilisation heat treatment will be carried out on the springs after rolling, preferably for 5 minutes between 450 °C and 480 °C. This heat treatment, when applied to UGI® 4062 makes it possible to obtain better slackening resistance between 20 and 300 °C than that of the 1.4310 grade.

Uniform corrosion: This corrosion mode mainly occurs in the chemical industry during manufacturing of sulphuric or phosphoric acids. An accelerated test to simulate this type of corrosion is carried out by measuring the density of dissolution or activity current density on a polarisation curve in a sulphuric acid environment of 2 moles/litre (200 g/itre) at 23 °C. The graph below gives the values of dissolution current in µA/cm2 of the UGI® 4062 and the 1.4301 on wire rod (after mechanical polishing with SiC 1200 paper). The lower the values, the better the uniform corrosion resistance

The UGI® 4062 grade has a uniform corrosion resistance comparable to that of the 1.4301 grade (in the above-mentioned accelerated corrosion test conditions).

In these preparation conditions, the first corrosion pits appeared after 1,000 hours for the 1.4301 and after 2,000 hours for UGI® 4062 duplex.

PITTING POTENTIAL: The purpose is to determine, on a polarisation curve, the potential from which corrosion pitting will appear; the higher the potential, the better the pitting corrosion resistance.

Two media with neutral pH were tested: 0.02 moles/litre of NaCl (0.71 g/L of chlorides) at 23 °C; 0.86 moles/litre of NaCl (30.4 g/L of chlorides) at 35 °C.

The graphs below give the values of the pitting potential in the two above-mentioned media in mV/SCE (Saturated Calomel Electrode) for two surface conditions: wire rod mechanically polished with SiC1200 paper and raw unpolished wire rod.

The UGI® 4062 grade provides better pitting corrosion resistance when compared to the 1.4301 grade (in the above-mentioned accelerated corrosion test conditions).

Crevice corrosion: This mode of corrosion appears in confined environments whose main characteristic is to become acid during the corrosion process; one of the parameters which simulate this mode of corrosion is represented by the depassivation pH, that is to say the pH of dissolution of the passive film. This pH is determined by an electrochemical test, by plotting a polarisation curve in a sodium chloride medium at 2 moles/litre at 23 °C. The lower the depassivation pH, the better the crevice corrosion resistance. The graph provided in the picture part of the datasheet gives the values of the depassivation pH.

UGI® 4062 provides better crevice corrosion resistance than the 1.4301 grade (in the above-mentioned accelerated corrosion test conditions).

Intergranular corrosion: UGI® 4062 gives a conforming result in the Strauss test (ASTM A262 practice E).

Stress corrosion cracking: The austenitic-ferritic grades have better resistance to this mode of corrosion than austenitic grades. In the EFC 17 medium of the European Federation of Corrosion (165 g/L of sodium chloride; pH = 4.5) for a hydrogen sulphide pressure varying from 0.05 to 0.5 bar and at 80 °C, no cracks were detected on UGI® 4062 test specimens loaded to 100 % Rp0.2, after 720 hours of test.

Lathe turning: In lathe turning operations, UGI® 4062 is at the same level as the 1.4301 grade (AISI 304) in terms of cutting tool wear (Vb15/0.15 test with tool SECO TM2000 CNMG 120408-MF4). However, adaptation of the cutting tips may become necessary to maintain the same productivity as with the 1.4301 grade (AISI 304), in particular because the UGI® 4062 chips brake less easily, which can generate bar turning difficulties.

Solution annealing: To decrease the hardness and restore the ductility of UGI ® 4062 after cold working, a heat treatment can be carried out for 30 to 60 minutes between 950 °C and 1,050 °C, followed with quick cooling.

UGI® 4062 has satisfactory workability between 1,000 °C and 1,200 °C. At equal temperature, the forging loads of UGI® 4062 are lower than those of austenitic stainless steels, and its ductility is slightly lower. It is recommended to heat it up between 1,150 and 1,200 °C and, after hot transformation, to cool it down quickly (with oil or water) to avoid brittling precipitations which may appear between 850 °C and 400 °C, this being the reason why operating temperatures above 300 °C are not recommended.

Drilling: When drilling with high speed steel drill bits with diameter 4 mm (Perfor HSS 6-5-2) without central liquid cooling, UGI® 4062 allows maximum chip flows 40 % greater than those obtained with 1.4301 (AISI 304) thanks to a widened Optimum Operating Zone (OOZ*) towards high feed speeds. When drilling with 6 mm one-piece coated carbide drill bits (Gühring RT100F) with central liquid cooling, UGI® 4062 allows maximum chip flows greater by 25 % than those obtained with the 1.4301 grade thanks to a widened Optimum Operating Zone (OOZ*).

Available products:

Other presentations: please consult the supplier

For flat product please contact Insdusteel Arcelor Mittal Group

Pickling / Passivation / Electro-polishing: The operation conditions generally used for a 1.4301 austenitic stainless steel need to be adapted on a case by case basis (please consult us).

UGI® 4062 can be welded using the following processes: friction welding, resistance welding, arc welding with or without filler metal wire (MIG, TIG, covered electrode, plasma, flux, etc.), LASER beam welding electron beam welding, etc.

As there is no molybdenum in UGI® 4062, this grade does not generate any risks of formation of brittle phase (sigma phase) during welding operations. Its weldability is close to that of the 1.4307 grade (AISI 304L). When compared with this grade, UGI® 4062 even provides better warranty as regards to hot cracking during welding.

However, in order to optimise the impact strength of the welds, it is highly recommended to select a linear welding energy high enough to limit the quantity of ferrite in the weld metal zone (WMZ) and in the Heat Affected Zone (HAZ) below 70 %. Different filler metal wires can be used to weld UGI® 4062, depending on the required mechanical characteristics and corrosion resistance of the welds. The main types of filler metals are: