{"id":3525,"date":"2026-02-10T17:29:30","date_gmt":"2026-02-10T08:29:30","guid":{"rendered":"https:\/\/www.mako-metal.com\/eng\/?p=3525"},"modified":"2026-02-12T08:33:53","modified_gmt":"2026-02-11T23:33:53","slug":"titanium-is-resistant-to-hot-spring-corrosion%ef%bd%9cexplaining-the-problem-of-metal-rusting-and-dissolving-in-hot-springs-with-supporting-data","status":"publish","type":"post","link":"https:\/\/www.mako-metal.com\/eng\/archives\/3525","title":{"rendered":"Titanium is Resistant to Hot Spring Corrosion\uff5cExplaining the Problem of Metal Rusting and Dissolving in Hot Springs with Supporting Data"},"content":{"rendered":"<header>\n<div class=\"kicker\"><strong>&lt;Technical Column \/ Specifications for Construction &amp; Hot Spring Sites&gt;<\/strong><\/div>\n<p class=\"lead\">At hot spring sites, recurring problems arise: &#8220;The appearance deteriorates,&#8221; &#8220;Bolts fail first,&#8221; and &#8220;Replacement work is unpredictable.&#8221;<br \/>\nThis is no coincidence\u2014hot springs present <strong>the most challenging environment<\/strong> for metals.<br \/>\nThis column uses corrosion resistance test results (under strong acidic spring and high-temperature spring conditions) as evidence to explain why <strong>titanium<\/strong> offers overwhelming advantages while clarifying in practical construction terms, how titanium delivers <strong>the best cost performance (lowest TCO)<\/strong> when considering long-term durability and safety.<\/p>\n<div id=\"toc_container\" class=\"no_bullets\"><p class=\"toc_title\">contents<\/p><ul class=\"toc_list\"><ul><li><ul><li><ul><li><a href=\"#Table_of_Contents\"><span class=\"toc_number toc_depth_4\">0.0.0.1<\/span> [Table of Contents]<\/a><\/li><\/ul><\/li><\/ul><\/li><\/ul><\/li><li><a href=\"#Why_metals_rust_in_hot_springs_The_essence_of_hot_spring_corrosion\"><span class=\"toc_number toc_depth_1\">1<\/span> Why metals rust in hot springs (The essence of hot spring corrosion)<\/a><\/li><li><a href=\"#Environmental_conditions_of_hot_springs_Strong_acidity_high_temperature_chloride_eg_Kawayu_Hot_Spring_Noboribetsu_Hot_Spring\"><span class=\"toc_number toc_depth_1\">2<\/span> Environmental conditions of hot springs: Strong acidity, high temperature, chloride (e.g., Kawayu Hot Spring \/ Noboribetsu Hot Spring)<\/a><\/li><li><a href=\"#Test_Result_The_corrosion_rate_of_pure_titanium_is_000_mmyear_Difference_compared_to_grade_304_stainless_steel_and_aluminum\"><span class=\"toc_number toc_depth_1\">3<\/span> Test Result: The corrosion rate of pure titanium is 0.00 mm\/year (Difference compared to grade 304 stainless steel and aluminum)<\/a><ul><li><a href=\"#Comparison_of_corrosion_rate_mmyear_Test_results\"><span class=\"toc_number toc_depth_2\">3.1<\/span> Comparison of corrosion rate (mm\/year) (Test results)<\/a><\/li><li><a href=\"#Implications_from_a_designer8217s_perspective\"><span class=\"toc_number toc_depth_2\">3.2<\/span> Implications from a designer&#8217;s perspective<\/a><\/li><\/ul><\/li><li><a href=\"#Examples_of_short-term_deterioration_occurring_on-site_Immersion_exposure_and_bolts\"><span class=\"toc_number toc_depth_1\">4<\/span> Examples of short-term deterioration occurring on-site: Immersion exposure and bolts<\/a><ul><li><a href=\"#1_Immersion_exposure_at_Noboribetsu_hot_spring_source_Grade_304_stainless_steel_and_aluminum_dissolved\"><span class=\"toc_number toc_depth_2\">4.1<\/span> (1) Immersion exposure at Noboribetsu hot spring source: Grade 304 stainless steel and aluminum dissolved<\/a><\/li><li><a href=\"#2_Comparison_Using_Bolts_Zinc-Plated_Steel_Corrodes_Rapidly_Titanium_Bolts_Remain_Stable\"><span class=\"toc_number toc_depth_2\">4.2<\/span> (2) Comparison Using Bolts: Zinc-Plated Steel Corrodes Rapidly, Titanium Bolts Remain Stable<\/a><\/li><\/ul><\/li><li><a href=\"#Conclusion_on_design_judgment_Why_titanium_offers_the_best_cost-performance_ratio_30-year_TCO\"><span class=\"toc_number toc_depth_1\">5<\/span> Conclusion on design judgment: Why titanium offers the best cost-performance ratio (30-year TCO)<\/a><ul><li><a href=\"#Cost_items_that_matter_in_terms_of_the_TCO_in_hot_spring_areas\"><span class=\"toc_number toc_depth_2\">5.1<\/span> Cost items that matter in terms of the TCO in hot spring areas<\/a><\/li><\/ul><\/li><li><a href=\"#Recommended_applications_in_hot_spring_areas_grating_bolts_roofs_signs_etc\"><span class=\"toc_number toc_depth_1\">6<\/span> Recommended applications in hot spring areas (grating, bolts, roofs, signs, etc.)<\/a><ul><li><a href=\"#Grating_around_hot_spring_sources_drainage\"><span class=\"toc_number toc_depth_2\">6.1<\/span> Grating (around hot spring sources, drainage)<\/a><\/li><li><a href=\"#Bolts_and_nuts_Essential_for_safety_and_maintenance\"><span class=\"toc_number toc_depth_2\">6.2<\/span> Bolts and nuts (Essential for safety and maintenance)<\/a><\/li><li><a href=\"#Roofs_Both_non-decorative_and_decorative\"><span class=\"toc_number toc_depth_2\">6.3<\/span> Roofs (Both non-decorative and decorative)<\/a><\/li><li><a href=\"#Signage_LandscapeBrand\"><span class=\"toc_number toc_depth_2\">6.4<\/span> Signage (Landscape\/Brand)<\/a><\/li><\/ul><\/li><li><a href=\"#Important_notes_regarding_specifications_Dissimilar_metal_contact_galvanic_corrosion_and_installation_details\"><span class=\"toc_number toc_depth_1\">7<\/span> Important notes regarding specifications: Dissimilar metal contact (galvanic corrosion) and installation details<\/a><ul><li><a href=\"#Three_Practical_Fundamentals\"><span class=\"toc_number toc_depth_2\">7.1<\/span> Three Practical Fundamentals<\/a><\/li><\/ul><\/li><li><a href=\"#Frequently_Asked_Questions_FAQ\"><span class=\"toc_number toc_depth_1\">8<\/span> Frequently Asked Questions (FAQ)<\/a><ul><li><a href=\"#Q1_Isn8217t_stainless_steel_grade_304_sufficient_for_hot_spring_areas\"><span class=\"toc_number toc_depth_2\">8.1<\/span> Q1. Isn&#8217;t stainless steel (grade 304) sufficient for hot spring areas?<\/a><\/li><li><a href=\"#Q2_Where_should_I_prioritize_to_stop_metal_rusting_in_hot_springs\"><span class=\"toc_number toc_depth_2\">8.2<\/span> Q2. Where should I prioritize to stop metal rusting in hot springs?<\/a><\/li><li><a href=\"#Q3_Isn8217t_titanium_expensive\"><span class=\"toc_number toc_depth_2\">8.3<\/span> Q3. Isn&#8217;t titanium expensive?<\/a><\/li><li><a href=\"#Q4_Is_it_true_that_titanium_doesn8217t_rust\"><span class=\"toc_number toc_depth_2\">8.4<\/span> Q4. Is it true that titanium doesn&#8217;t rust?<\/a><\/li><li><a href=\"#Designs_considering_hot_spring_corrosion_Building_strength_from_the_start\"><span class=\"toc_number toc_depth_2\">8.5<\/span> Designs considering hot spring corrosion: Building strength from the start<\/a><\/li><\/ul><\/li><li><a href=\"#ConclusionHot_Springs_Titanium_Simultaneously_Designing_Durability_and_Operational_Efficiency\"><span class=\"toc_number toc_depth_1\">9<\/span> Conclusion\uff5cHot Springs \u00d7 Titanium: Simultaneously Designing Durability and Operational Efficiency<\/a><\/li><\/ul><\/div>\n<h5><span id=\"Table_of_Contents\"><strong>[Table of Contents]<\/strong><\/span><\/h5>\n<div class=\"toc\" aria-label=\"\u76ee\u6b21\">\n<ol>\n<li><a href=\"#sec1\">Why metals rust in hot springs (The essence of hot spring corrosion)<\/a><\/li>\n<li><a href=\"#sec2\">Environmental conditions of Hot Springs: Strong acidity, high temperature, chloride<\/a><\/li>\n<li><a href=\"#sec3\">Test Result: The corrosion rate of pure titanium is 0.00 mm\/year (Difference compared to grade 304 stainless steel and aluminum)<\/a><\/li>\n<li><a href=\"#sec4\">Examples of short-term deterioration\u00a0occurring on-site: Immersion exposure and bolts<\/a><\/li>\n<li><a href=\"#sec5\">Conclusion on design judgment: Why titanium offers the best cost-performance ratio (30-year TCO)<\/a><\/li>\n<li><a href=\"#sec6\">Recommended applications in hot spring areas (grating, bolts, roofs, signs, etc.)<\/a><\/li>\n<li><a href=\"#sec7\">Important notes regarding specifications: Dissimilar metal contact (galvanic corrosion) and installation details<\/a><\/li>\n<li><a href=\"#sec8\">Frequently Asked Questions (FAQ)<\/a><\/li>\n<\/ol>\n<\/div>\n<\/header>\n<section id=\"sec1\">\n<h2><span id=\"Why_metals_rust_in_hot_springs_The_essence_of_hot_spring_corrosion\">Why metals rust in hot springs (The essence of hot spring corrosion)<\/span><\/h2>\n<p>The phenomenon of <em>metal rusting in hot springs<\/em> cannot be explained simply by <em>being outdoors<\/em>.<br \/>\nCorrosion in hot spring areas (hot spring corrosion) is accelerated primarily by the simultaneous action of the following three factors:<\/p>\n<ul>\n<li><strong>Strong acidity<\/strong>: The lower the pH, the easier it is for the protective film on the metal surface to break down.<\/li>\n<li><strong>High Temperature<\/strong>: Chemical reactions progress faster as temperature rises, increasing corrosion rates.<\/li>\n<li><strong>Chloride ions<\/strong>: A factor that readily induces pitting corrosion (pinhole-like localized corrosion) in stainless steel.<\/li>\n<\/ul>\n<p>In other words, for materials, hot springs are places where <em>acid<\/em>, <em>heat<\/em>, and <em>salt (chloride)<\/em> converge.<br \/>\nUnder these conditions, even metals that are generally considered <em>highly corrosion-resistant<\/em> can deteriorate much faster than expected.<br \/>\nAs a result, the frequency of component replacement increases, leading to accumulated costs for scaffolding, shutdowns, safety measures, and landscape repairs.<\/p>\n<\/section>\n<section id=\"sec2\">\n<h2><span id=\"Environmental_conditions_of_hot_springs_Strong_acidity_high_temperature_chloride_eg_Kawayu_Hot_Spring_Noboribetsu_Hot_Spring\">Environmental conditions of hot springs: Strong acidity, high temperature, chloride (e.g., Kawayu Hot Spring \/ Noboribetsu Hot Spring)<\/span><\/h2>\n<p>The below table summarizes conditions for representative hot spring areas.<br \/>\nThe crucial point is that the <em>type of harshness<\/em> varies by hot spring location (strong acid type, high temperature type, etc.).<\/p>\n<table>\n<thead>\n<tr>\n<th>Item<\/th>\n<th>Kawayu Hot Spring (Example)<\/th>\n<th>Noboribetsu Hot Spring (Example)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Acidity<\/td>\n<td><strong>pH 1.7<\/strong><\/td>\n<td><strong>pH 2.3<\/strong><\/td>\n<\/tr>\n<tr>\n<td>Chloride ion<\/td>\n<td><strong>1430 mg\/L<\/strong><\/td>\n<td><strong>24.7 mg\/L<\/strong><\/td>\n<\/tr>\n<tr>\n<td>Source temperature<\/td>\n<td><strong>50 deg C<\/strong><\/td>\n<td><strong>Over 90 deg. C<\/strong><\/td>\n<\/tr>\n<tr>\n<td>Remark<\/td>\n<td>Hot spring conditions containing acidic, sulfur-containing, and ferrous (Fe\u00b2\u207a) elements<\/td>\n<td>Hot spring conditions containing elements such as sulfur springs and salt springs<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"small\">*Source: Key points extracted from materials provided by Company N (March 19, 2024) (numbers\/temperatures).<\/p>\n<p>A pH of 1.7 indicates strong acidity, and temperatures exceeding 90 deg. C represent extremely harsh conditions for architectural hardware.<br \/>\nRather than <em>addressing hot spring corrosion after it occurs<\/em>, <strong>eliminating corrosion scenarios at the material selection stage<\/strong> is the most rational approach for long-term operation.<\/p>\n<\/section>\n<section id=\"sec3\">\n<h2><span id=\"Test_Result_The_corrosion_rate_of_pure_titanium_is_000_mmyear_Difference_compared_to_grade_304_stainless_steel_and_aluminum\">Test Result: The corrosion rate of pure titanium is 0.00 mm\/year (Difference compared to grade 304 stainless steel and aluminum)<\/span><\/h2>\n<p>Below is the result of metal weight loss testing using Kawayu hot spring water.<br \/>\nTest temperature: <strong>77 deg. C<\/strong>, Test duration: <strong>3 hours<\/strong><br \/>\nUnder these conditions, the difference between materials is clearly evident in the <em>figures<\/em>.<\/p>\n<div class=\"grid\">\n<div class=\"card\">\n<h3><span id=\"Comparison_of_corrosion_rate_mmyear_Test_results\">Comparison of corrosion rate (mm\/year) (Test results)<\/span><\/h3>\n<ul>\n<li><strong>Titanium\/IP gold titanium: 0.00 mm\/year <\/strong>(Excellent corrosion resistance)<\/li>\n<li><strong>Grade 304 stainless steel: 1.27 mm\/year <\/strong>(Significant corrosion rate with pitting corrosion)<\/li>\n<li><strong>Aluminum: 5 mm\/year or more <\/strong>(Extremely high value)<\/li>\n<\/ul>\n<p class=\"small\">*Source: Provided materials (Kawayu Hot Spring water immersion test results)<\/p>\n<\/div>\n<div class=\"card\">\n<h3><span id=\"Implications_from_a_designer8217s_perspective\">Implications from a designer&#8217;s perspective<\/span><\/h3>\n<p>Corrosion rate indicates <em>how quickly a material thins<\/em>.<br \/>\nA result of 0.00 mm\/year suggests that, at least under the test conditions, <strong>practical wall thinning is virtually nonexistent<\/strong>.<br \/>\nIn contrast, grade 304 stainless steel and aluminum can develop significant wall thinning and pitting corrosion even within short periods.<\/p>\n<p>The value of titanium lies not only in its <em>rust resistance<\/em>\u00a0but also in <strong>eliminating the need for replacement planning<\/strong> or <strong>minimizing replacement frequency<\/strong>.<\/p>\n<\/div>\n<\/div>\n<p>The key point here is not to limit the comparison to material costs alone.<br \/>\nIn hot spring environments, if the material fails prematurely, it triggers a chain of subsequent costs.<br \/>\n<strong>Scaffolding, safety management, shutdowns, landscape restoration, and complaint handling<\/strong>\u2014when these are totaled, titanium often delivers the best overall cost performance in the long run, even if the initial cost is slightly higher.<\/p>\n<\/section>\n<section id=\"sec4\">\n<h2><span id=\"Examples_of_short-term_deterioration_occurring_on-site_Immersion_exposure_and_bolts\">Examples of <em>short-term deterioration<\/em> occurring on-site: Immersion exposure and bolts<\/span><\/h2>\n<h3><span id=\"1_Immersion_exposure_at_Noboribetsu_hot_spring_source_Grade_304_stainless_steel_and_aluminum_dissolved\">(1) Immersion exposure at Noboribetsu hot spring source: Grade 304 stainless steel and aluminum <em>dissolved<\/em><\/span><\/h3>\n<p>According to the result of immersion exposure testing on grade 304 stainless steel, titanium, and aluminum alloy at Noboribetsu Hot Spring source, the aluminum and grade 304 stainless steel dissolved after four months of exposure.<br \/>\nThis clearly demonstrates that hot spring corrosion is <em>faster than imagined<\/em>.<\/p>\n<h3><span id=\"2_Comparison_Using_Bolts_Zinc-Plated_Steel_Corrodes_Rapidly_Titanium_Bolts_Remain_Stable\">(2) Comparison Using Bolts: Zinc-Plated Steel Corrodes Rapidly, Titanium Bolts Remain Stable<\/span><\/h3>\n<p>The problem of <em>metal rusting in hot springs<\/em>\u00a0often manifests first in <strong>bolts<\/strong>, <strong>nuts<\/strong>, and <strong>fasteners<\/strong> rather than in plates or main structures.<br \/>\nImmersion exposure using Kawayu hot spring water showed that while <strong>zinc-plated steel bolts corroded significantly within days to weeks<\/strong>, <strong>titanium bolts maintained their appearance even after three weeks<\/strong>.<\/p>\n<p>If bolts deteriorate first, it&#8217;s not just a simple <em>replacement<\/em>.<br \/>\nIt leads to reduced fastening strength, safety risks, potential component detachment, and increased effort for regular inspections and repairs.<br \/>\nIn hot spring resort construction, the approach of <strong>designing from the smallest structural and safety-critical components (bolts)<\/strong> is effective.<\/p>\n<\/section>\n<section id=\"sec5\">\n<h2><span id=\"Conclusion_on_design_judgment_Why_titanium_offers_the_best_cost-performance_ratio_30-year_TCO\">Conclusion on design judgment: Why titanium offers the best cost-performance ratio (30-year TCO)<\/span><\/h2>\n<p>The impression that <em>titanium is expensive<\/em>\u00a0applies only when looking at the material cost alone.<br \/>\nIn hot spring areas, material replacement becomes the <em>core of operational costs<\/em>.<br \/>\nHere, we simplify this by organizing it as the 30-year TCO (Total Cost of Ownership).<\/p>\n<div class=\"card\">\n<h3><span id=\"Cost_items_that_matter_in_terms_of_the_TCO_in_hot_spring_areas\">Cost items that matter in terms of the TCO in hot spring areas<\/span><\/h3>\n<ul>\n<li><strong>Material Cost<\/strong>: Incurs only once at the start (Titanium is higher)<\/li>\n<li><strong>Replacement cost<\/strong>: Parts cost + labor (increases with frequency)<\/li>\n<li><strong>Scaffolding\/Protective Covering\/Safety Management<\/strong>: Prone to high costs depending on site conditions<\/li>\n<li><strong>Business interruption\/access restrictions<\/strong>: Owner&#8217;s loss (more significant in tourist areas)<\/li>\n<li><strong>Landscape restoration\/cleaning<\/strong>: Rust stains\/dirt directly damage brand reputation<\/li>\n<\/ul>\n<\/div>\n<p>Test results suggest pure titanium has a corrosion rate of 0.00 mm\/year, while grade 304 stainless steel and aluminum show significantly higher corrosion rates.<br \/>\nIn other words, when considering hot spring corrosion, titanium is a material highly likely to <em>dramatically reduce replacement frequency<\/em>.<\/p>\n<p>This translates to the highest cost performance when considering long-term durability and safety.<br \/>\nFor architectural decision-making, it is rational to judge not based solely on material unit cost, but as <strong>a specification design that includes renewal plans (replacement frequency)<\/strong>.<\/p>\n<div class=\"note\"><strong>To summarize in one sentence:<\/strong><br \/>\nIn hot spring areas, <em>stabilizing operations with materials that don&#8217;t need replacement<\/em> ultimately reduces both costs and risks more than <em>replacing cheap materials repeatedly<\/em>. Titanium is central to this choice.<\/div>\n<\/section>\n<section id=\"sec6\">\n<h2><span id=\"Recommended_applications_in_hot_spring_areas_grating_bolts_roofs_signs_etc\">Recommended applications in hot spring areas (grating, bolts, roofs, signs, etc.)<\/span><\/h2>\n<p>The number of cases where titanium is being adopted and used in trial installations at hot spring areas is increasing.<br \/>\nThe key is to prioritize <em>areas most susceptible to hot spring corrosion damage<\/em>.<\/p>\n<div class=\"grid\">\n<div class=\"card\">\n<h3><span id=\"Grating_around_hot_spring_sources_drainage\">Grating (around hot spring sources, drainage)<\/span><\/h3>\n<p>The area near the source has the most severe corrosion conditions, and regular replacement tends to become routine.<br \/>\nThere is an example of a trial installation using titanium gratings at Noboribetsu Sengen Park.<br \/>\nThe value of titanium increases significantly in locations that are key points along tourist routes.<\/p>\n<\/div>\n<div class=\"card\">\n<h3><span id=\"Bolts_and_nuts_Essential_for_safety_and_maintenance\">Bolts and nuts (Essential for safety and maintenance)<\/span><\/h3>\n<p>The problem of metal rusting in hot springs often begins at fastening points.<br \/>\nIn environments where galvanized steel deteriorates rapidly, adopting titanium bolts is effective.<br \/>\nThis specification eliminates the risk of <em>the main body being fine while the fasteners corrode first<\/em>.<\/p>\n<\/div>\n<div class=\"card\">\n<h3><span id=\"Roofs_Both_non-decorative_and_decorative\">Roofs (Both non-decorative and decorative)<\/span><\/h3>\n<p>Hot spring areas have corrosion factors floating in the air, which can accelerate deterioration in roofs, eaves, and sheet metal.<br \/>\nTitanium contributes to reducing leakage risks and decreasing the frequency of replacements over a long period of time.<\/p>\n<\/div>\n<div class=\"card\">\n<h3><span id=\"Signage_LandscapeBrand\">Signage (Landscape\/Brand)<\/span><\/h3>\n<p>Hot spring areas hold high landscape value; rust stains and grime can damage brand reputation.<br \/>\nMaintaining appearance over time not only impacts operational costs directly but also preserves the value as a tourist destination.<\/p>\n<\/div>\n<\/div>\n<p>There is no need to convert everything to titanium at once.<br \/>\nA practical approach is to gradually expand the application of titanium in this order: <em>close to the source<\/em>, <em>difficult to replace<\/em>, <em>safety-critical<\/em>, and <em>directly impacting the landscape<\/em>.<\/p>\n<\/section>\n<section id=\"sec7\">\n<h2><span id=\"Important_notes_regarding_specifications_Dissimilar_metal_contact_galvanic_corrosion_and_installation_details\">Important notes regarding specifications: Dissimilar metal contact (galvanic corrosion) and installation details<\/span><\/h2>\n<p>While titanium is highly resistant to hot spring corrosion, proper <strong>fitting (interfaces)<\/strong> is crucial for architectural hardware.<br \/>\nParticular attention should be paid to <strong>galvanic corrosion<\/strong>, where dissimilar metals come into contact and corrosion progresses due to potential differences.<br \/>\nHot spring areas tend to be rich in electrolytes (ions), making the risk of galvanic corrosion more likely to manifest.<\/p>\n<div class=\"card\">\n<h3><span id=\"Three_Practical_Fundamentals\">Three Practical Fundamentals<\/span><\/h3>\n<ol>\n<li><strong>Avoid direct contact between dissimilar metals<\/strong>: Separate them using insulating washers, resin spacers, etc.<\/li>\n<li><strong>Ensure water does not pool:<\/strong> Use drainage, slope, and ventilation to avoid <em>permanent wetting<\/em>.<\/li>\n<li><strong>Prioritize fastener strength<\/strong>: Bolts are often the starting point for metal corrosion in hot springs.<\/li>\n<\/ol>\n<\/div>\n<p>We can provide documentation outlining considerations on specifications tailored to project conditions (water quality, temperature, chloride content, installation location) and specific components (bolts, gratings, roofs, signs, etc.). Aligning specifications during the design phase reduces operational uncertainty.<\/p>\n<\/section>\n<section id=\"sec8\">\n<h2><span id=\"Frequently_Asked_Questions_FAQ\">Frequently Asked Questions (FAQ)<\/span><\/h2>\n<h3><span id=\"Q1_Isn8217t_stainless_steel_grade_304_sufficient_for_hot_spring_areas\">Q1. Isn&#8217;t stainless steel (grade 304) sufficient for hot spring areas?<\/span><\/h3>\n<p>When hot spring corrosion conditions (strong acidity, high temperature, chloride) overlap, even grade 304 stainless steel can experience pitting corrosion and wall thinning.<br \/>\nA test result indicates a corrosion rate of 1.27 mm\/year (pitting corrosion onset) for grade 304 stainless steel.<br \/>\nThe harsher the conditions, the greater the advantage of titanium.<\/p>\n<h3><span id=\"Q2_Where_should_I_prioritize_to_stop_metal_rusting_in_hot_springs\">Q2. Where should I prioritize to stop <em>metal rusting in hot springs<\/em>?<\/span><\/h3>\n<p>The recommended priority order is: #1 Areas near the source or steam, #2 Safety-critical fastening points (bolts), #3 Areas difficult to replace (requiring scaffolding), #4 Areas with high aesthetic value (signage, etc.). Even partial optimization yields benefits.<\/p>\n<h3><span id=\"Q3_Isn8217t_titanium_expensive\">Q3. Isn&#8217;t titanium expensive?<\/span><\/h3>\n<p>While the material cost per unit tends to be high, in hot spring areas, renewal costs (scaffolding, shutdowns, safety management) often become the dominant expense.<br \/>\nMaterials that reduce replacement frequency often prove cheaper over a 30-year TCO, which is the essence of <em>maximum cost performance<\/em>.&#8221;<\/p>\n<h3><span id=\"Q4_Is_it_true_that_titanium_doesn8217t_rust\">Q4. Is it true that titanium <em>doesn&#8217;t rust<\/em>?<\/span><\/h3>\n<p>We cannot guarantee 100% corrosion resistance (as it varies by spring quality and conditions), but test results suggest pure titanium has a corrosion rate of 0.00mm\/year.<br \/>\nAt the very least, there is supporting data showing it outperforms grade 304 stainless steel and aluminum under the same conditions, making it a highly rational material choice.<\/p>\n<div class=\"cta\">\n<h3 style=\"margin-top: 0;\"><span id=\"Designs_considering_hot_spring_corrosion_Building_strength_from_the_start\">Designs considering hot spring corrosion: Building strength from the start<\/span><\/h3>\n<p style=\"margin: 0 0 10px;\">\u00a0If you share the <em>hot spring corrosion conditions (pH, temperature, chloride content)<\/em>, <em>application location<\/em>, and <em>desired decorative pattern<\/em>,we can propose optimal specifications, including hot spring titanium.<\/p>\n<p style=\"margin: 0;\">\u25b6 For consultation regarding adoption and technical inquiries, <a href=\"https:\/\/www.mako-metal.com\/eng\/contact\">please contact us.<\/a><\/p>\n<\/div>\n<\/section>\n<section>\n<h2><span id=\"ConclusionHot_Springs_Titanium_Simultaneously_Designing_Durability_and_Operational_Efficiency\">Conclusion\uff5cHot Springs \u00d7 Titanium: Simultaneously Designing <em>Durability<\/em> and <em>Operational Efficiency<\/em><\/span><\/h2>\n<p>Hot spring corrosion, where metals rust in hot springs, is a problem that directly impacts not only the appearance of materials but also safety, maintenance, and landscape value.<br \/>\nTest results suggest pure titanium exhibits a corrosion rate of 0.00 mm\/year, clearly outperforming grade 304 stainless steel and aluminum.<\/p>\n<p>Therefore, titanium becomes the most cost-effective choice (minimizing TCO) from the perspectives of <em>long-term durability<\/em>, <em>safety<\/em>, and reducing replacement costs.<\/p>\n<\/section>\n<footer>\n<p class=\"small\">*This column is intended to provide general technical information. Final material selection and specification decisions should be made after consulting experts, taking into account local conditions (spring quality, temperature, concentration, installation environment, dissimilar metal interfaces, etc.).<\/p>\n<p class=\"small\">\u00a9 Toyo Stainless Polish Industry Co., Ltd.<\/p>\n<\/footer>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>&lt;Technical Column \/ Specifications for Construction &amp; Hot Spring Sites&gt; At hot spring sites, recurring problems arise: &#8220;The appearance deteriorates,&#8221; &#8220;Bolts fail first,&#8221; and &#8220;Replacement work is unpredictable.&#8221; This is no coincidence\u2014hot springs present the most challenging environment for metals. This column uses corrosion resistance test results (under strong acidic &#8230; <\/p>\n","protected":false},"author":1,"featured_media":3535,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/posts\/3525"}],"collection":[{"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/comments?post=3525"}],"version-history":[{"count":12,"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/posts\/3525\/revisions"}],"predecessor-version":[{"id":3543,"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/posts\/3525\/revisions\/3543"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/media\/3535"}],"wp:attachment":[{"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/media?parent=3525"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/categories?post=3525"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mako-metal.com\/eng\/wp-json\/wp\/v2\/tags?post=3525"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}