Description 

Properties: After heat treatment, the mechanical properties of the product are significantly improved, enabling it to withstand compressive strengths of up to 1100-1300Mpa (160-190ksi). However, this grade of material is not suitable for temperatures above 300ºC (572ºF) or very low temperatures. Nevertheless, it still has good corrosion resistance and can resist the effects of atmosphere, diluted acids and salts. Its corrosion resistance is comparable to 304 and 430 stainless steel.

17-4PH is a martensitic precipitation-hardened stainless steel. Its main performance characteristic is that it is easy to adjust the strength level, which can be achieved only by changing the heat treatment process. Martensitic transformation and aging treatment are the main strengthening methods, through which precipitation hardening phase is formed, thereby improving the strength and hardness of the material. In addition, 17-4PH also has excellent attenuation properties, which can effectively resist corrosion fatigue and water drop erosion, so that it can maintain good performance in a variety of harsh environments.

Parameter

Chemical composition: 17-4PH / 0Cr17Ni4Cu4Nb steel chemical composition

Standard

ASTM is a widely used standard, and its A693 grade 630 (AMS 5604B) and UNS S17400 are two important parts of it. EURONORM's 1.4542X5CrNiCuNb 16-4 and AFNOR's Z5 CNU 17-4PH are also widely accepted standards. DIN 1.4542 is also a common standard.

Corrosion resistance

The corrosion resistance of the 17-4 PH alloy is better than that of any other standard hardenable stainless steel. In most cases, its corrosion resistance is no less than 304. If there is a risk of stress corrosion cracking, the higher curing temperature must be higher than 550oC (1022oF), preferably 590oC (1094oF). In the chloride medium, the best tempering temperature is 550oC-1022oF. In H2S medium, the best tempering temperature is 590oC-1094oF. This alloy is vulnerable to erosion or crack corrosion in static seawater. Its corrosion resistance in the petrochemical, food processing and paper industries is the same as 304L grade.

machining

We can machine 17-4 PH alloys that have been treated with solution or in the quenched and hardened state, and the processing conditions vary with the hardness of the material. We usually use high-speed cutting tools or lubricated charring knives for processing. If the customer is very strict about tolerances, we should also take into account the dimensional changes that may occur during heat treatment.

Instructions

The technical information provided here reflects our high level and comprehensive knowledge at the time of compiling this information, but the content may change slightly as our research on corrosion resistant products progresses. We recommend that you reconfirm the above information when making an inquiry or placing an order. In addition, every product has some special circumstances when it is applied. The information provided here is only a description of the product, and only when our company makes a written document can it be regarded as our guarantee and commitment.

process

The thermoforming should be carried out in the temperature range of 950-1200oC (1742-2192oF). The complete heat treatment consists of solid annealing, cooling (below 25oC) and curing (at a given temperature).

slice

Thermal cutting (plasma, saw, etc.): Taking into account the thermal metamorphic parts, the cutting procedure for this grade should be appropriate. After cutting, it is ground to remove the oxide layer. Mechanical cutting: cutting, stamping, cold sawing, etc.

weld

17-4 PH alloys are available for the following welds: SMAW, GTAW, PAW and GMAW. After preliminary testing (checking for cracks and toughness of the weld metal), SAW welding can be performed. Due to the solidification of ferrite, the possibility of hot cracking and hot deterioration of weld metal is reduced. In general, no preheating is required, and the intermediate temperature should be controlled at 120°C (248°F). After a complete heat treatment (solid solution annealing + quenching hardening), the toughness will be enhanced. Due to its martensitic structure, the low oxygen content in the weld metal makes it maintain good toughness and ductility. In order to avoid cold cracking, the intervention of hydrogen should be avoided as much as possible. Can 17-4 PH alloys be combined with the same filler metal (e.g. E 630 (AWS A5.4))? ER 630 (AWS A5.9) for welding. If the mechanical properties of 17-4PH are not taken into account in welding, the metal can also be filled with austenite, and there is no need for heat treatment afterwards.