Hardfacing Layer Research Articles

Development of NiCrSiBC Weld Hardfacing Approach for P91 Steels Used in Steam Turbine Components

Abstract: P91 steels are used as substrate material for steam turbine components like bush, valve seat internals, and engineering valves. These components have hardfacing of cobalt-based material to reduce the high temperature wear loss and to improve the surface hardness. However, delamination failure and higher heat affected zone (HAZ) hardness were identified challenges for P91 steels. Hence, this demands the development of a suitable weld hardfacing approach to resolve the said challenges. In this work, NiCrSiBC (Colmonoy 6) has been considered as a hardfacing material to replace cobalt-based Stellite 6 material due to elimination of radiation activity, lower cost, and higher coating hardness. FCAW and PTA techniques were used to deposit buffer layer (SS-309L) and hardfacing layer (NiCrSiBC) respectively. Sample WBL (with deposition of buffer layer) and sample WOBL (without deposition of buffer layer) are considered approaches to study the metallurgical characterization for each case. Higher coating hardness, lower HAZ hardness and lower Fe dilution were observed in sample WBL. Cr7C3, Cr2B, and Cr5B3 hard phases in block shape together with ϒ- nickel matrix solid solution was observed in coating region of sample WBL. Overall, sample WBL approach was considered to overcome weld hardfacing challenges for steam turbine industries.

ТЕХНИЧЕСКОЕ СОСТОЯНИЕ И ИЗНОСЫ ЛЕВЫХ НОЖЕЙ СКОРОСТНЫХ ПЛУГОВ СЕРИИ ПСКУ МЕТОДЫ ИХ ТОРМОЖЕНИЯ И УСТРАНЕНИЯ

High-speed plowing forces signifi cant changes in the design of the working elements of the plow. Such changes greatly aff ected the wear pattern and, consequently, called for modifi ed technical processes of restoring and strengthening. The working body design includes a plowshare, the function of which is performed by the left-side knife. The research purpose was to control the technical condition of the above-mentioned parts of the PSKu-series plow; study the geometry, location, and magnitude of wear; and develop restoration and hardening technologies. The residual values of thickness and width were used as the criteria for wear since they infl uence the recovery method. These values were controlled by standard measuring instruments – calipers and height gauges. The hardness measured by the Rockwell method (HRC) was used as a criterion for the mechanical properties of the construction material. Studies have shown that the wear on the working surfaces has a rather complex geometry, which is associated with the specifi cs of the force action of the soil. This defect should be eliminated because the probability of extreme wear in thickness increases when the part rotates. The authors proposed that the wear on the left-side knife should be eliminated by patching with a low-carbon electrode and subsequent hardening with surfacing reinforcement. It has been experimentally established that the wear amounts to about 7 mm in thickness and no more than 8 mm in width for a knife with a 45…54 HRC blade. The wear is caused by a hard-facing layer with a hardness of 73…74 HRC on the backside. High-quality heat treatment ensures an increased resistance of the part to abrasive wear. For left-side knives, it is expedient to apply electrode surfacing with a low-carbon rod and the subsequent hardening by surfacing reinforcement.

Experimental Studies of Stellite-6 Hardfaced Layer on Ferrous Materials by Tig Surfacing Process

Hardfacing is the cheapest technique and it is the deposition of coatings of hard, wear resistant materials on a worn or new component that is subjected to wear, impact, high temperature, and oxidation. Weld hard facing is used to deposit thick layers of hard material by Tungsten Inert Gas (TIG) welding technique. This layer acts as a sacrificial layer at the point of impact and safeguards the base metal from wear out and corrosion. It is also used to fill the worn out part of a component there by increasing its durability and lifetime. A thick layer of stellite-6 of width 1mm is deposited on the base metals (i.e mild steel and EN-8) varying the weld currents as 120A, 140A, 160A. Vickers Hardness testing machine is used to measure the hardness of the hardfaced components and the variation of the hardness with varying weld current for both substrates. The specimens are subjected to oxidation at elevated temperature of 973K by muffle furnace for 5, 10, 15 hours duration and to study the oxidation rate with respect to different processing currents. The microstructural analysis is performed using optical microscopy on hardfaced samples. The aim of the paper is to study the effect in rate of oxidation, hardness, and microstructure with respect to varying parameters in stellite-6 hardfacing on ferrous materials.

Comparison of Properties of Hardfaced Layers Made by a Metal-Core-Covered Tubular Electrode with a Special Chemical Composition.

In this article, the results of research on the metal-mineral-type abrasive wear of a wear-resistant plate made by a tubular electrode with a metallic core and an innovative chemical composition using the manual metal arc hardfacing process were presented. The properties of the new layer were compared to the results of eleven wear plates manufactured by global suppliers, including flux-cored arc welding gas-shielded (FCAW-GS, Deposition Process Reference Number: 138), flux-cored arc welding self-shielded (FCAW-SS, Deposition Process Reference Number: 114), automated hardfacing, and manual metal arc welding (MMAW, Deposition Process Reference Number: 111) hardfacing T Fe15 and T Fe16 alloys, according to EN 14700:2014. Characterization of the hardfaced layers was achieved by using hardness tests, optical microscopy, confocal microscopy, scanning electron microscopy, and EDS (Energy Dispersive Spectroscopy) and X-ray diffraction analyses. Based on wear resistance tests in laboratory conditions, in accordance with ASTM G65-00: Procedure A, and surface layer hardness tests, in accordance with PN-EN ISO 6508-1, the wear plates most suitable for use in metal-mineral conditions were chosen. The results demonstrated the high metal-mineral abrasive wear resistance of the deposit weld metal produced by the new covered tubular electrode. The tubular electrode demonstrated a high linear correlation between the surface wear resistance and the hardness of the metal matrix of the tested abrasive wear plates. In addition to hardness, size, shape, the dispersion of strengthening phases, and the base metal content, depending on hardfacing technology and technological parameters, impact wear resistance is represented by volumetric loss caused by effect-free or constrained dry abrasive medium contact. The presented results can be used in machine part material selection and wear planning for applications in inspection, conservation, and regeneration interval determination. The obtained results will be applied in a real-time wear rate prediction system based on the measurement of the working parameters.

TIG Overlap Welding Affecting Hard-Faced Weld Metal Properties on JIS-S50C Carbon Steel

This paper aimed to study an overlap distance (OL) of hard-faced welding bead in a tungsten inert gas (TIG) welding on the JIS-S50C carbon steel surface. Hard-faced weld metal was produced on an outside surface of the cylinder, using TIG welding with a high chromium flux-cored wire electrode. Welding process parameters were a welding current of 150–210 A and a hard-faced layer of 1–3. The experimental results were summarized as follows. An increase in welding current increased the weld width and the penetration but decreased the weld convex. It also increased the hardness and wear resistance of hard-faced weld metal. The increase of a weld overlap distance resulted in a decrease in the dilution effect in weld metals and an increase in the hardness and wear resistance. An increase in the hard-faced weld metal layer also resulted in a decrease in the dilution effect, resulting in an increase in the hardness and wear resistance.

Microstructure and Wear Resistance of WC and High Chromium Cast Iron Hardfacing Layers

The WC and high chromium cast iron (HCCI) welded layers were prepared on Q235 low carbon steel by hardfacing technique in order to improve high-temperature performance. The microstructure and mechanical properties of the welded layer were investigated. It was found that Fe3W3C is the major strengthening phase of the WC welded layer. Furthermore, a high-temperature three-body abrasive wear experiment was designed and conducted on the welded layers. The results show that the wear resistance of the WC welded layer was much better than that of the HCCI welded layer at both room and high temperatures. During the high-temperature abrasive wear process, the Fe3W3C phase can effectively strengthen the matrix and hence, contribute to improved wear resistance.

The influence of chromium content on wear and corrosion behavior of surface alloyed steel with Fe(16−x)Crx(B,C)4 electrode

In this study, the electrodes containing Fe(16−X)CrX(B,C)4 (X = 3,4,5) were used for surface alloying on an AISI 1010 steel substrate. The alloy structure of the coating exhibits in-situ composite structure with a large amount of reinforcing carbides and borides phases as to be hypoeutectic and hypereutectic structure in the surface alloyed layer. The obtained composition of the alloy shows that it contains much more interstitial hard phases in the alloyed layer than the conventional hardfacing alloys used in the industrial applications for the hardfacing of the steels. The morphological and microstructural properties showed that layer microstructure changed from hypoeutectic to hypereutectic structure with an increase in chromium content. The results of these studies revealed that the microstructure of hardfacing layers consists of interstitial phases of α(Fe-Cr) and (Fe,Cr)23(C,B)6 as major phases, (Fe,Cr)2(C,B) and (Fe,Cr)7(C,B)3 as minor phases in the in-situ composite structure. The composite hardness’ in the alloyed surface layers of the Fe(16−X)CrX(B,C)4 alloys ranged from 711 HV to 1164.3 HV. Wear test against alumina ball shows that the friction coefficients of the surface alloyed layers decreased with increase in applied loads and decrease in chromium content in the Fe(16−X)CrX(B,C)4 alloy composition. Coefficient of friction ranged from 0.55 to 0.79 in the present study. Wear rates of the surface alloyed steels caused to increase with decrease in chromium content and increase in applied loads. The wear rates of the alloyed layer changed between 3.07 × 10 and 5 mm3/m and 6.95 × 10−5 mm3/m. The corrosion resistance of the alloyed layers was measured by a potentiostatic polarization test. Icorr and Ecorr of the coated layers changed from 1.813 to 9.965 µA/cm2 and −704.786 to −745.792 mV, depending on alloyed layer compositions. With increasing chromium content, the corrosion resistance of the coating layer has changed in a nobler side.

Abrasive wear characteristics and microstructure of Fe-based overlaid ploughshares in different field conditions

In the present research, two different Fe-based claddings, namely SZ (Fe–Cr, Fe–33.37Cr–3.83C) and ZK (Fe–Mo, Fe–8.18Mo–4.5Cr–0.65C) were overlaid on EN-42 steel substrate by Manual Metal Arc Welding (MMAW) process with an aim to enhance the abrasive wear characteristics of the steel. The microstructural and abrasive wear behavior of overlaid samples was investigated in comparison with bare steel (EN-42) in actual field conditions at two different moisture levels (0–3% and 14–17%). Optical microscopy, scanning electron microscope (SEM), X-ray diffraction (XRD), and hardness testing were performed to characterize the microstructural and mechanical properties of bare and overlaid steel samples. The effect of moisture content on abrasive wear resistance of tillage tools and tillage quality has also been evaluated. The results revealed that the variables such as carbide shape, size, distribution, and matrix structure of hardfacing influence the wear resistance of hardfacings. The SZ alloy showed higher abrasive wear resistance than ZK alloy due to the formation of M23C6 and M7C3 carbides in the hardfaced layer. The moisture content of the soil also affected the abrasive wear resistance of the substrate and different hardfacings materials, which in turn influence the tillage efficiency of the tool. The wear rate of bare and overlaid ploughshares is almost 3 times higher in dry field conditions (0-3% moisture) as compared to moist conditions (14–17%). The wear resistance indices (WRI) for SZ and ZK overlaying were found to be 1.85 and 1.48 respectively for low moisture conditions, and 1.9 and 1.54 for the moist condition.

Properties of new-generation hybrid layers combining hardfacing and nitriding dedicated to improvement in forging tools\u2019 durability

This article deals with the subject of layers produced in a hybrid process combining hardfacing and nitriding. These layers are characterized by improved resistance to wear, which arises from the synergy between favorable materials during hardfacing and nitriding treatment. Tests were conducted on hot-work tool steel (H11) samples. Hardfaced layers consisting of three layers were applied to these samples, where layers were made from two materials—Robotool 46 and Hardface VMolc powder wires. Next, samples of both materials were nitrided using ZeroFlow gas nitriding technology, with control of potential aimed at obtaining a diffusion layer without a white zone of nitrides on the surface. The next step was to investigate the properties of hardfaced layers and of layers hardfaced after nitriding treatment. Conducted tests covered observations of the microstructure, microhardness measurements as a function of distance from the surface, measurement of stresses in the surface layer by means of X-ray diffraction, and tribological tests. Obtained test results show that hybrid layers combining hardfacing and nitriding may be suitable for improving the lifetime of tools applied in hot forging processes.

Evaluation of the slurry erosion resistance of the body materials of oil & gas drill bits with a modified abrasive waterjet

Fixed-cutter drill bit is a key component of the whole drilling system. Its quality and service life greatly depend on the erosion resistance of the bit body. A limitation to the successful development of improved erosion resistant materials is the lack of a meaningful, and standardized test method. In this work, a slurry erosion test method has been developed to fill this technical void, which incorporates environmental aspects of fixed-cutter drill bits and is capable of closely simulating the downhole conditions. Wear resistant materials that form the body of a drill-bit are created either by a liquid metal infiltration of copper-based metal matrix composite or through the deposition of a hardfacing layer on a hardened and tempered steel. Examples of both materials are described herein, where laboratory testing correlates to the downhole conditions, validating that the developed slurry erosion test is appropriate and meaningful.

Fracture failure analysis of coal mill shaft

During the operation of No.2 boiler in a power plant, the fracture of a coal mill shaft occurred. The fracture causes of the coal mill shaft were found by macroscopic inspection, metallographic inspection, chemical composition analysis, fracture morphology analysis and mechanical property inspection. The experimental results showed that: 1. The external surface of the coal mill shaft had been welded, and the poor welding process resulted in a large number of welding defects such as cracks, slag inclusions and lack of fusion in the overlaying layer; 2. The improper hot working process of the coal mill shaft resulted in the abnormal metallographic structure of the shaft, and the existence of serious reticulated ferrite and brittle widmanstatten structure resulted in the low strength of the shaft. 3.Because of the existence of the cyclic torsion and bending stress of large load, the initial crack source occurred at the welding position of the hardfacing layer, and then extended in the form of fatigue, eventually causing the coal mill shaft to break. Three factors led the high cycle and low stress fatigue fracture of the coal mill shaft.

Weld Overlay Technique using Different Filler Rod Size to Overcome Internal Corrosion of Low Carbon Steel Base Metal

Overlay welding is commonly used to repair and replace the affected corroded surface of the base metal of a component. In other words, it is used to restore the original dimensions of the component. Weld overlay usually applies a corrosion resistant or hard facing layer onto the base metal. This experiment is to determine the suitable filler rod size in repairing corroded low carbon steel (LCS) base metal, respectively to the affected area and to identify the type of distortion occurring on the weldment. It is also to examine the microstructure of the joint between the overlay weld and corroded low carbon steel base metal using SEM/EDX. The overlay welding process was conducted on the corroded samples using SMAW process at defined attacked corroded areas. Filler electrode E-7018 with two diameter sizes of 3.2mm and 2.6mm were selected. It was found that the bigger electrode size produced higher degree of distortion angle compared to smaller electrode size. Resulting from the metallographic and SEM/EDX analysis, the joint between weld overlay and corroded LCS were fused well without any sign of oxides or other impurities present. Overlay welding also remove the sign of chloride ions that cause the LCS base metal to corrode. Thus, the repairing technique using overlay welding was found successful in repairing corroded LCS base metal. Therefore, the most suitable electrode size to do overlay welding on corroded low carbon steel base metal is 2.6 mm diameter electrode.

Sintering and Wear Behavior of a FeCrCB Hardfacing Alloy Applied by Tape Casting: A Study of Cooling Rate Effect

This study presents a simple process to deposit a hardfacing coating on a steel substrate, based on the sintering of metallic powder applied by tape casting (by a slurry of metallic powder suspension onto a steel substrate) thus avoiding the use of traditional welding processes and their variants. The effect of the cooling of hardfacing after the sintering process, by air at room temperature or by quenching in water, was studied. This new method ensures a good metallurgical bonding between the substrate steel and the hardfacing layer and shows mechanical property improvement on coated pieces, similar to those exhibited by hardfacing coatings produced by several kinds of welding processes. The characterization of the hardfacing coatings was made by X-ray diffraction, optical microscopy, scanning electron microscopy, microhardness and wear resistance according to the ASTM G65 standard. The characterization results show that the presented faces are: M7C3, M3C, MC, M2B and M23B6; there are three different phases in the micrograph glass phase, eutectic phase and hard phase with a volumetric fraction of 0.14, 0.20 and 0.66, respectively, for the air cooled and 0.15, 0.16 and 0.69 when quenched in water. The average microhardness value for the parts cooled in air was 832.5 HV and for that cooled in water was 958.9 HV, and the wear resistance was a mass loss of 0.219 and 0.128 g for parts cooled in air and water, respectively. These results show that the hardfacing coating could have twice the hardness and wear resistance than that observed for the boron steel used as a substrate.

Effect of hard facing processes on Mild steel A-36 by arc welding

Hard facing is a metalworking process where harder material applied to the base material with the help of different welding processes like Arc welding, TIG welding and Plasma arc welding processes. This process is called Hard facing because the deposited surfaces are harder than the base metal usually. Hard facing is one of the most common and economical way to improve the surface property, life cycle and performance of the components. In the present investigation, a detailed study was done to understand the effect of two different hard facing electrodes Zed alloy 550 and Nikko Steel 600Hv on Mild Steel A36 is carried out. Using Arc welding process, single and double layer of weld were applied by Hard facing electrode. The micro hardness, Pin on Disc (POD) wear test were carried out on the samples. It is found that the Zed alloy 550 double layer gives wear resistance 5.5 times higher in comparison to base material without hard facing process. The hardness value of Zed alloy 550 multilayers, Nikko steel Hv-600 single layer, Nikko steel Hv600 Multi-layer was found to increase by 3.52, 2.75, 3.44 times respectively. The micro hardness, wear rate and microstructure of the hard-facing layer were affected by chemical compositions like Mn-C-Cr-V-Si. The hardness and wear resistance of the hard-facing layer increases with increasing the amount of carbon and chromium contents.

Wear behavior and metallurgical characteristics of particle reinforced metal matrix composites produced by hardfacing: A review

Earth moving equipments and its components are generally susceptible to wear and erosion owing to the severe environmental conditions. Low carbon steel with nickel based Hardfacing layer is preferred to increase the wear and erosion resistance of these components. Also, corrosion performance is found to be increased. Particle Reinforced Metal Matrix Composite (PRMMC) is an emerging technology in hardfacing that will enhance the tribological performance of the components by adding hard metal or ceramic particles in the existing alloys. Tungsten Carbide (WC) is often selected as reinforcement in PRMMC to improve the wear and erosion behavior, however, there is only few researches conducted to study tribological behavior of WC hardface by varying the amount of WC reinforcement. So, this paper reviewed recent research on PRMMC (especially WC) hardfacing and correlated important findings from them with WC reinforced hardface.

Modeling and optimizing the laser parameters for corrosion resistance in 316 SS laser hardfaced surface using tungsten carbide

Laser hardfacing Tungsten Carbide was fabricated on 316 stainless steel surfaces using a synchronization powder feeding technique by 4 kW Diode laser (co axial laser) apparatus. An attempt has been made to optimizing the process parameters of laser such as Laser Power (P), Travel Speed (T), Defocusing Distance (D) and Powder feed rate (F). The influence of the processing variables on corrosion rate is discussed. The experiments were conducted using design matrix based on a four factor and five level central composite rotatable design. An empirical relationship was developed to predict the corrosion rate of Tungsten carbide hardfaced layer using response surface methodology (RSM) technique. The optimized parameters and the influenced parameter were identified. The interaction effects of input process parameters of laser hardfacing were discussed. The corrosion properties were analyzed by Pitting corrosion method. The pitting method results show that the hardfacing is mainly to increase the corrosion resistance. With the increase of laser power, corrosion resistance and micro hardness of the hardfaced surface have been improved.

Investigations on hardfacing and wear characteristics of nickel-based Inconel 625 overlaid welds over AISI 347 pipe

The article focuses on investigating the effect of process parameters and wear behaviour of overlaid welds. Gas metal arc (GMAW) hardfacing is widely employed for repairing and to improve the performance of the engineering components. In this research, hardfacing is performed in the range of 130–150 A with filler wire of Inconel alloy (IN625) on the AISI 347 substrate. Successful overlaid welds were made for 150 A current at a speed of 250 mm/min and observed a continuous and even layer on the substrate. A primary current of 150 A or more can be used to overlay a uniform and continuous layer to the substrate by varying the welding speed. Higher contact angle and lower dilution were noticed at higher current and higher overlaying speeds. The increase in primary current increased the dilution and reduced the contact angle with lower bead width. In-depth microstructural examination exposed defect-free Inconel 625 hardfaced overlays with better metallurgical bonding at the interface. The overlay weld thickness varied in the range of 1.50–2.62 mm on the substrate. The hardfaced layers contain dendritic and interdendritic precipitates of Nb along the AISI 347 substrate. The intermetallic precipitates in the upper region of the overlaid weld are combined with columnar dendrites to form the Laves and (Nb, Ti) C phases. The EDS plots show the lower concentration of Fe in the IN625 overlay welds. EDS examination shows the Fe elemental dispersion and increase in the wt% of Fe in the partially melted zone of the substrate. The as-deposited overlay consists of Ni3Si, M23C6 and Ni3B phases. The micro-Vickers hardness of the hardfaced layers revealed the presence of HAZ in the substrate by GMAW process. At the applied load of 90 N, The wear rate increased with the increase in applied load on the overlaid welds from 20 to 90 N. The wear trend varies with applied load and wear time. The successfully deposited overlay welds can be suitable for worn surfaces and engineering applications to protect the stainless steels.

Microstructure, Microhardness, and Wear Properties of Cobalt Alloy Electrodes Coated with TiO2 Nanoparticles

In this paper, the influence of TiO2 nanoparticle coating on cobalt-based electrodes was studied. Different coating treatment times were applied, and the results were compared to the hard-faced layer obtained with unmodified electrodes. The hard facing was done in three layers, the first being a Ni-based interlayer, followed by two layers of corrosion and wear-resistant Co-based Stellite 6 alloy. Pin-on-disc wear testing was applied, along with the metallographic study and hardness measurements of the hard-faced layers. Furthermore, energy-dispersive X-ray spectroscopy (EDS) analysis was conducted. It was found that the microstructural properties, as well as microhardness profiles, are modified in hard-faced layers obtained with modified electrodes. Interdendritic distances are altered, as are the dendrite growth directions. Titanium oxides are formed, which, along with the present complex carbides, increase the wear resistance of the hard-faced layers compared to layers obtained with untreated electrodes.

Effect of Heat Input on Micro-Hardness and Shear Strength of Inconel 625 Hardfacing onto AISI 347 Steel pipes by GMAW Process

Inconel 625 is one of the most accepted hardfacing material having good corrosion resistance properties at high temperature applications. Hardfacing is the deposition of a hard surface layer to the base metal by means of welding. The benefit of hardfacing is resistance to environmental stresses mainly corrosion at elevated temperatures. Thermal input plays a critical role for manufacturing good hardfaced components with respect to weld bead geometry, cooling rate, etc. In the present study, an L9 orthogonal array of input parameters were carried out with different heat input combinations using 98% Argon + 2% CO2 as shielding gas. Single layer hardfacing was done. The bead-on-pipe welding trials and macroscopic analysis were carried out to find the optimal welding parameters that yielded minimum dilution. The hardfaced layer thickness varies from 1.88mm to 2.58mm on substrate following optimum welding parameters. Visual inspection results reveal that most of welds of higher heat input conditions possess good quality. It is visually observed that width of weld increases with increase in welding heat input. It is noticed that in the range of 200-250 mm/min welding speed and 150A of welding current, good reinforcement and weld bead width at optimum penetration is observed in the experiments. Shear strength test and micro-hardness test were performed over test samples prepared from hardfaced part. Results revealed that both micro-hardness and shear strength of the hardfaced layer were more than that of base metal and values of both increased with increase in heat input. The Inconel 625 hardfaced layer exhibited 32 % higher hardness than the substrate material AISI 347.

The indentation and wear performance of hardfacing layers on H13 steel for use in high temperature application

TBM (Full face rock tunnel boring machine) is a large tunnel excavation lining complete equipment which has been widely used in many practical fields. The main components of TBM rock breaking are the disc cutters. Due to the harsh working environment of TBM, such as high temperature (400°C), wear, etc., the consumption of disc cutters is extremely high. Two welding methods used to repair cutters of TBM were analyzed in this paper: shielded metal arc welding (SMAW) and flux cored arc welding (FCAW). The microstructure at RT was investigated, the hardness, indentation modulus and wear resistance from RT to 400°C were also investigated. The results showed that the microstructure of FCAW hardfacing layers was finer. In the tests, the FCAW hardfacing layers showed better hardness and elastic modulus, both parameters reduced with increasing temperature. The FCAW hardfacing layers processed higher wear resistance from RT to 400°C. A thick oxide layer was observed, and it was partially removed when the temperature reached 400°C, and it has a certain protective effect on the worn surface. Therefore, the FCAW hardfacing layers are considered as a good choice due to the better mechanical performance from RT to 400°C.